The Second Day of Creation, Genesis Chapter 1


And God said, “Let there be a firmament in the midst of the waters, and let it separate the waters from the waters.” And God made the firmament and separated the waters which were under the firmament from the waters which were above the firmament. And it was so.
And God called the firmament Heaven. And there was evening and there was morning, a second day. (Genesis 1: 6-8) (Revised Standard Version-Catholic Edition).

The works of the six days of creation of Genesis chapter 1 and identifying those works can be followed with relative ease but the work of the second day and its interpretation appears historically to be troublesome or difficult as it appears even in the works of the Fathers of the Church who give various interpretations to the work of the second day of creation. Even today among biblical scholars, catholic or protestant, various interpretations are given. I hadn’t thought about this to much until about a month or so ago, following some thread here on this forum, the issue surfaced and made me think about it and do some research about it. I enlisted the help of St Thomas Aquinas and his exegesis of the work of the six days of creation found in his Summa Theologica, Part I.
Concerning the work of the second day of creation, St Thomas offers two explanations gathered from the Fathers of the Church. Firstly, some fathers explain the firmament as the starry heaven. Secondly, others explain the firmament as the cloudy region of the air in which water is condensed and falls to the earth to water it. According to the first explanation, waters have been placed by God above the starry heavens. This is the interpretation given even today by some modern biblical scholars and found in at least some catholic bibles such as the New American Bible. In fact, it seems to be the mainstream interpretation of modern catholic biblical scholars. The second explanation we could simply call the earth’s atmosphere in which the waters above the earth are collected in the clouds and falls to the earth in the form of rain, snow, or hail. In the Summa Theologica, St Thomas offers these two explanations of the firmament but he doesn’t seem to give a personal opinion of one over the other but seems to simply say that the scriptures lends itself to both.

At this point, I began to search the Holy Scriptures for clues as to the meaning of the making of the firmament on the second day which God calls heaven. What precisely did Moses mean by the firmament? It obviously had to do with the separation of the waters which covered the earth in the early stages of God forming the universe. The difficulty of the interpretation of the work of the second day lies in that God calls the firmament heaven and the firmament is mentioned in the works of days 4 and 5. At the same time, God seems to have already created the heavens in the beginning, “In the beginning God created the heavens and the earth” (Gen. 1:1). But, the heavens had no light as we can understand by the words “and darkness was upon the face of the deep” (Gen. 1:2. And then God created the light and separated the light from the darkness. And there was evening and morning, one day (Gen. 1:3-5). By this Aquinas understands that the ‘formlessness’ of the heavens, that is, being without light, is given formation by the creation of light. For light gives beauty to the heavens and the heavens are the source of light. We can also reason that by the creation of light which God called day, and He called the darkness night, and there was evening and morning, one day, that according to the understanding of the former peoples and ancients, the heavens were set in a diurnal motion. Now, if the heavens weren’t made until the second day, how could there be a first day of which the Scriptures speak of in Gen. 1:3-5 and where is the light and darkness or day and night?




Thank you for your exegesis. It’s rare to hear these kinds of things discussed today.

I’ll take you up here.

By “heavens” and “earth”, I think we are given to understand the angels, or the invisible things (“heavens”), and by “earth”, matter, and the visible things. To back this up, I appeal to the Nicene Creed, which declares “I believe in one God, the Father Almighty, maker of heaven and earth, of all things visible and invisible”.

By water, we are given to understand formless matter; in the same way that water fills whatever it’s contained in and takes its shape, so the formless matter takes the form of whatever God gives it. This explanation is also in perfect harmony with modern science, which holds that for about 400,000 years after the Big Bang, there were no stars, only a haze of hydrogen and helium atoms. This sufficiently explains Gen. 1:2.

Now, the Hexaemeron proper.

Light in this sense, is meant to indicate that visible things were created, since light makes things visible. Thus just as in perfect darkness nothing can be seen, so that everything is invisible, when light is created it indicates matter’s creation (as well as space).

Now, considering what was said above about waters, the waters do not mean waters as such, but implies (relatively) formless matter, which was created the day before. This formless matter of hydrogen and helium atoms is separated into nebulae, which is what we are given to understand by the separation of waters above the firmament, namely empty space, from those below, namely the nebulae.

But, you will ask, surely this can’t be the literal sense of Scripture, since there is no way that Moses (or the inspired redactor) knew about these things. I answer: indeed this is not the literal sense; the literal sense of the creation week is an anthropomorphism designed to impress upon the readers and hearers that God created the world and all things in it. But, since God is the principal author of Scripture, it certainly can’t be denied that He could use an account, not intended to teach cosmology per se, to have a hidden sense which does accord with modern cosmology.

Anyway, I hope this was helpful,
Benedicat Deus,


I agree with Latinitas that the meaning traditionally attached to the passage by the Jews is the most important thing.

At the concrete level some scholars think the major part of Gen 1 represents a restoration of Earth after a major flood. This was used by the Jews as a creation story. Some scientists have discerned three major worldwide floods (impacting the majority of the more densely populated areas) in the last 20,000 years.


Fr. McMullin had some helpful things to say about the firmament, I think:

"Before leaving Aquinas, it would be worthwhile to pause a moment to see how he handled a discrepancy between the Genesis account, taken literally, and the accepted natural knowledge of his day. The Creator is said to have set a “firmament” on the second day between the waters above and those beneath. The “firmament” would originally have been understood to be a solid divider of some sort, supporting the waters above. But in the Aristotelian universe there was no such divider. The “firmament” ought then to be interpreted as the air, Aquinas says, an element not mentioned in the Genesis account because it might have seemed, at the time the account was composed, to be no more than incorporeal space:

It should rather be considered that Moses [assumed to be the author of Genesis] was speaking to ignorant people, and that out of consideration for their weakness he put before them only such things as are apparent to sense… It is not evident to all that air also is corporeal, for there have been philosophers who said that air is nothing and called the space filled by air a vacuum. Moses, then, while he expressly mentions water and earth, makes no express mention of air by name, to avoid setting before ignorant persons something beyond their knowledge. (Summa Theologica, I, q. 68, a. 3, c.)

*The exegetical principle that Aquinas invokes has come to be called the “principle of accommodation.” Moses could not have been expected to make his narrative conform to the truths of natural philosophy of a later age since this would have thoroughly confused the audience of his own day. The task of the theologian, therefore, is to interpret the text, thus accommodated, to the best natural knowledge of his own time." *

Fr. Jacki also noted: “… when Basil and Augustine discussed the firmament, they forgot their sound precepts. Augustine in particular went to great lengths in claiming that since the Bible spoke in a realist way about the firmament, it had to be real. Then he identified as the firmament an allegedly humid layer of air beyond the orbit of Saturn. All his proofs came from astrology where Saturn is connected with humidity and coldness.”

The McMullin essay is at

The Jaki essay is at


Concerning interpreting Scripture, the Catechism lays out a framework:


"109 In Sacred Scripture, God speaks to man in a human way. To interpret Scripture correctly, the reader must be attentive to what the human authors truly wanted to affirm, and to what God wanted to reveal to us by their words.75

"110 In order to discover the sacred authors’ intention, the reader must take into account the conditions of their time and culture, the literary genres in use at that time, and the modes of feeling, speaking and narrating then current. "For the fact is that truth is differently presented and expressed in the various types of historical writing, in prophetical and poetical texts, and in other forms of literary expression."76

"111 But since Sacred Scripture is inspired, there is another and no less important principle of correct interpretation, without which Scripture would remain a dead letter. "Sacred Scripture must be read and interpreted in the light of the same Spirit by whom it was written."77

"The Second Vatican Council indicates three criteria for interpreting Scripture in accordance with the Spirit who inspired it.78

"112 1. Be especially attentive “to the content and unity of the whole Scripture”. Different as the books which compose it may be, Scripture is a unity by reason of the unity of God’s plan, of which Christ Jesus is the center and heart, open since his Passover.79

The phrase "heart of Christ" can refer to Sacred Scripture, which makes known his heart, closed before the Passion, as the Scripture was obscure. But the Scripture has been opened since the Passion; since those who from then on have understood it, consider and discern in what way the prophecies must be interpreted.80

“113 2. Read the Scripture within “the living Tradition of the whole Church”. According to a saying of the Fathers, Sacred Scripture is written principally in the Church’s heart rather than in documents and records, for the Church carries in her Tradition the living memorial of God’s Word, and it is the Holy Spirit who gives her the spiritual interpretation of the Scripture (”. . . according to the spiritual meaning which the Spirit grants to the Church"81).

"114 3. Be attentive to the analogy of faith.82 By “analogy of faith” we mean the coherence of the truths of faith among themselves and within the whole plan of Revelation.

"The senses of Scripture

"115 According to an ancient tradition, one can distinguish between two senses of Scripture: the literal and the spiritual, the latter being subdivided into the allegorical, moral and anagogical senses. The profound concordance of the four senses guarantees all its richness to the living reading of Scripture in the Church.

"116 The literal sense is the meaning conveyed by the words of Scripture and discovered by exegesis, following the rules of sound interpretation: "All other senses of Sacred Scripture are based on the literal."83

"117 The spiritual sense. Thanks to the unity of God’s plan, not only the text of Scripture but also the realities and events about which it speaks can be signs.

"1. The allegorical sense. We can acquire a more profound understanding of events by recognizing their significance in Christ; thus the crossing of the Red Sea is a sign or type of Christ’s victory and also of Christian Baptism.84

"2. The moral sense. The events reported in Scripture ought to lead us to act justly. As St. Paul says, they were written “for our instruction”.85

"3. The anagogical sense (Greek: anagoge, “leading”). We can view realities and events in terms of their eternal significance, leading us toward our true homeland: thus the Church on earth is a sign of the heavenly Jerusalem.86

"118 A medieval couplet summarizes the significance of the four senses:

The Letter speaks of deeds; Allegory to faith;
The Moral how to act; Anagogy our destiny.87

"119 "It is the task of exegetes to work, according to these rules, towards a better understanding and explanation of the meaning of Sacred Scripture in order that their research may help the Church to form a firmer judgement. For, of course, all that has been said about the manner of interpreting Scripture is ultimately subject to the judgement of the Church which exercises the divinely conferred commission and ministry of watching over and interpreting the Word of God."88

"But I would not believe in the Gospel, had not the authority of the Catholic Church already moved me.89"

Regarding Genesis, science has little to nothing relevant to say. This simply means science is, by definition, excluding itself from proving miraculous events. Just as Jesus Christ literally raised the dead on more than one occasion.



I haven’t run across so much discussion of this subject as you have presented. I think scripture has several levels of meaning, but reading scripture can be like walking a tightrope, and it’s easy to fall off, and that, particularly in Gen 1, where the description of the creation of everything is described.

If it helps at all, what I’ve read, probably in the many Jewish commentaries on my bookshelf, is that “heaven and earth” in verse 1 is a Hebrew idiom for “everything.” And this idiom has a proper name, merism, which is employed in other places in Hebrew scripture. The use of heaven in the second verse is the individual use of the word, as distinct from the word earth.


Between the two verses, yes, heaven in its most particular sense, is the spiritual realm contrasted with all other physical realms.

I’ve read that Hebrew has seven words that are interpreted as heaven, leading Jewish thinkers to propose that there are seven levels of heaven. Paul speaks about “the third heaven” and we’ve heard the expression “seventh heaven” which is a reference to the highest and holiest level which is in the immediate location of God. The rabbis and sages considered that it would take 500 years of travel to pass through each of the levels of heaven. That remoteness helps us to understand the transcendence (loftiness or remoteness) of God (especially indicating His absolute holiness); the other characteristics of God, His immanence, His nearness, is described by His being so near as to hear the slightest whisper of prayer.

So, in one of the two equivalent but distinct expressions of Gen 1:1, “in the beginning, God created the heaven and the earth” is the most exquisite and profound statement of ancient theology, that there is one God (in spite of, it seems, the use of the plural elohim), separate from all visible forms of animate and inanimate matter, who is the Creator of all.

One of my first experiences in reading theology was in Fr. Jean Corbon’s book, Path to Freedom. For certain, I had a headache after reading every two pages of this book. Corbon is the principal author of the 4th section of the Catechism of the Catholic Church, on prayer (as I understand it). He refers to the first creation account in Genesis, attributed to the priestly source §, given its obvious poetic genre (with the repetition of phrases, for example), as the symphonic introduction of the Bible, an overture to what follows.

The English translation conceals further elements of its form and message, in that in the Hebrew, each verse consists of (I’ve read) seven Hebrew words or multiples of seven Hebrew words. By coincidence if not design, lists in Genesis usually have seven elements. (well, yes, 12 is an important number, and to know the truth, in Hebrew, Genesis is not divided into 50 chapters as we have it, it is divided into 12 sections – isn’t that interesting? why didn’t anybody ever tell you that?)

In parallel to the background radiation of the universe found everywhere which is the remnant of the big bang, I hear the eternal symphonic overture, which, even today, is just beginning.


In the op, it’s not obvious to me why the matter of the firmament is so important. Undoubtedly I have something to learn here.

In one source, the alternate word for "firmament’ is “expanse” and the underlying Hebrew word is most commonly used to refer to a piece of sheet metal. (Jewish Study Bible, 2nd Ed. Oxford U Press) in the literal sense.



Thank you for the response. The first part of your post sounds like St Augustine’s exegesis of the Hexaemeron. In Gen. 1:1, he identifies the heavens as you mention with the creation of the angels; earth and water in Gen. 1:1-2 with primary matter. Not that God created primary matter without form, for matter does not exist without form, but only in the order of nature and not that of time or duration.

Without going to look it up presently, the light God created on the first day, Augustine either holds to be knowledge God infused the angels with on their creation (morning and evening knowledge), sanctifying grace, or beatitude.

Blessings and peace,


Thanks for this response.

Yes, although what I meant by formless matter was more in the way St. Thomas described it, matter without form, comparatively, that is, without the beauty and distinction we think of today. Like a cloud of hydrogen or even other particles.

Thanks for your response,
Benedicat Deus,


Yes, the New American Standard Bible and the English Standard Bible use ‘expanse’ in place of firmament in Genesis 1. The Lutheran Church I believe use the ESB, at least here in the USA. Interestingly, if we plug in ‘expanse’ for firmament in Genesis 1, then I think it is more readily seen that the firmament or expanse mentioned in day 4 does not necessarily mean the same firmament or expanse or part of the heavens mentioned in day 2. The hebrew word translated firmament or expanse is raqia. Apparently, it means something expanded, stretched out, beaten or hammered thin out such as possibly a piece of metal or gold leaf. There are a number of occurances in the psalms and in the prophets such as Jeremiah and Isaiah too I believe where it is said that God stretched out the heavens like a tent or curtain.

The english word ‘firmament’ comes from the latin ‘firmamentum’. And the latin firmamentum comes from the greek septuagint translation of the Bible I believe. Aquinas defines it as something dense, firm, solid such as the density of the air holding up the water in the clouds before it falls to the earth. But the air is invisible but corporeal and material. Nothing is said of the details of the firmament or expanse in Genesis 1. The material nature of the visible heavens is invisible as the air is and even to this day it remains a mystery except for those objects we see in the heavens such as the moon, sun, and stars. If we were to understand by the hebrew word raqia something solid and material but thin, maybe by Moses’ choice of word here inspired by God he means that the matter of the heavens is of a very fine nature, almost spiritual, undetectable by the naked eye such as air is and even by modern instruments. Scientists today speculate that only about 4% of the matter in the universe is known by us. The rest is invisible and unknown by us either, they speculate, in the form of dark matter or dark energy. The idea of dark matter and dark energy and so forth I don’t really want to get in too however, but would prefer to stick with the simplicity with the Genesis 1 text and not get bogged down to much with modern day scientific theories. For the immediate audience of Genesis 1 was to an uncultured and simple people, though by this I do not mean a stupid people. But, Genesis 1, which is the inspired word of God, was written also for us, for the sophisticated as well as for the unsosphisticated.


Oh, I see, interesting. Well, I don’t think there is anything preventing you from applying such ideas (keeping in mind that the Big Bang and such are theories, maybe God began the heavens and the earth this way, maybe He didn’t, who knows) to the beginning of creation as it it laid down to us by God’s word. As it is laid down for us in Genesis 1, God gradually through the work of the six days brought the creation of the world to completion as we see it today and there was a certain formlessness to the heavens, water, and the earth as mentioned in Gen. 1: 2 but this is all the detail God saw fit to give us in the Bible.




I could perhaps run this further with day 3 plants which is the source of the testing ground “eat but dont eat”, day 5 birds and sea-monsters, angels good and angels bad, day 6 us, then a temptation of us day 6 by sea-monster Devil Satan from day 5 with source tree day 3, ultimately leading to destination day 2.


I don’t know if you guys will find this image as interesting as I did the first time I came across it. Very interesting to me when we talk about firmament etc. It is from “Reading the Old Testament” by Lawrence Boadt. Great book and resource.


The account from verse 2 to the end of chapter 1 was not originally a “creation account” but by the time it was incorporated in the Jewish Bible the meaning that was being attached to it was a creation meaning.

In the early verses, light and dark appeared fairly soon after the start of the narrative though sun and moon as such were not discernable till later on.

There is an awful lot of water in this story which gradually dwindles. And lack of discernible forms which gradually become apparent.

Nobody could remember further back than this. (And not a lot for some time after.)

Narratives all over the world begin at this point. Anything prior to that has theological overtones solely.


Well, possibly. On the other hand, it is written " And God called the firmament heaven" (Gen. 1: 8). So, the firmament has the nature of the heavens which were created before days “In the beginning God created the heavens and the earth” (Gen. 1:1). Now, it is the nature of the heavens that things can go through them. The moon, sun, and stars move through the heavens (and the earth too); water in the clouds falls through the heavens to the earth; the birds of heaven (Gen. 1: 26, 28, 30) fly through the heavens (across the firmament of the heavens [some translations] or under the firmament of the heavens [latin vulgate] (Gen. 1:20); we can throw a ball into the heavens and we send rockets into the heavens. But, we can’t throw a ball through the earth or through a stone or brick wall. Accordingly, if we talk about regions or boundaries in the heavens, it does not neccesarily follow that these “boundaries” imply an impassable boundary obviously. For example, we can talk about a distinction or ‘boundary’ between the earth’s atmosphere and that which is above the earth’s atmosphere or interplanetary space. But, things can pass through the “boundary” here such as light, rockets, meteors. Both, the earth’s atmosphere and the interplanetary space above the earth’s atmosphere in our solar system can be called heaven as a whole (of course the whole heavens includes all the starry heavens and galaxies), or the one can be termed a lower heaven and the other a higher heaven.

If, then, one understands by the firmament made on the second day the cloudy region of the air or that region of the heavens or the sky between the waters on the earth and the water in the clouds, than that which separates the two waters is simply heaven or the sky. Not the whole heavens of course but the lower part of them immediately above the earth but below the waters in the clouds. Above the waters in the clouds exists the firmament of the heavens (Gen. 1: 14,15,17) which was created before days “In the beginning God created the heavens and the earth” which received the light God created on the first day and where He separated the light from the darkness and day from night, and which God adorned with the sun, moon, and stars on the fourth day.

Interestingly, the interpretation of the firmament that God made on the second day as just explained above fits precisely the world as we see and observe it from earth. And the creation narrative of Genesis 1 is about the real world we live in, see, and experience in its completion on day seven on which God rested from all his work “he had done in creation.” The first six days God is working towards the completion of his creative activity in instituting the world which we find ourselves in and not only us but the early Hebrews too -to which this word of God was initially addressed too- and indeed of all humanity since the creation of Adam and Eve.

I can think of no other waters in the heavens above the waters on the earth that can be naturally thought of and sensibly observed except for those waters in the clouds that fall to the earth. At the same time, I’m not saying absolutely that there are not waters above the starry heavens, who knows? This would be a matter of faith and belief because if such waters existed they are beyond sensible observation. It is in this context that St Augustine says “These words of Scripture have more authority that the most exalted human intellect. Hence, whatever these waters are, and whatever their mode of existence, we cannot for a moment doubt that they are there.” Augustine here is talking about that interpretation of the work of the second day in which some fathers of the Church interpret the waters above the firmament as above the starry heavens and he does not exclude this interpretation. Augustine also held that the waters above the firmament can be interpreted to simply be the waters in the clouds and he actually recommends it thus “I consider this view of the question worthy of all commendation, as neither contrary to faith nor difficult to be proved and believed.” (quoted by St Thomas in the ST). In this interpretation of God’s work on the second day, I think we can say that God made clouds on this day. Clouds are a very beautiful phenomenon of the heavens especially of the colors they give to the sky at sunrise and sunset.

What I find intriquing about the whole discussion concerning the firmament God made on the second day is that the interpretation or explanation of this firmament as the whole visible heavens in which the moon, sun, and stars are placed and waters above the starry heavens opens up, one might say, a whole can of worms and endless speculations, not to mention in the least is how you reconcile this interpretation with the verses of Gen. 1: 1-5. On the other hand, if one understands by the firmament made on day two simply that part of the heavens or sky above the earth and below the waters in the clouds, or the cloudy region of the air (on a rainy day the clouds can seem to touch the earth and cover the hills and mountains, this though I think is a minor detail and the inspired author of Genesis 1 does not get stuck on minute details, the waters falling from the clouds is still above the waters on the earth), than the pieces of the puzzle as it were fit together and we have a description of this phenomena of the world exactly how we find and observe it. It corresponds to the real world around us.

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