Sexual sins why mortal sin?

Where in bible does this say this is the sin that leads to death? Just a friend of mine not catholic says sex is very important the same level as a spiritual connectin. She said that she would worry if a man wanted to wait until marriage as this shows he might not find her attractive, but I SAID it was lovely thing for a man to put God first. She said God does not expect us to not be sexual and God does not expect us to live in a spiritual bubble all time time. We are no good here if we can not relate to life in thus world! Have to admit I really think this is twisting Gods word. What you guys think? She is non denominational. Says we are saved even if we live sinful lifestyle but Jesus will change us. Lately not agreeing with some stuff but overall a lovely lady if God. Waiting on God and staying away from sinful lifestyle.

First off, a mortal sin is not mortal in and of itself because of the act committed, but because a grave act was done freely and in full knowledge of its gravity. That is, there are three conditions which must have occurred for a sin to be mortal and thus cut one off from the life of grace and require sacramental confession for absolution. 1. Grave Matter. 2. Full Knowledge. 3. Free Consent of the Will.

That said, sexual sins constitute grave matter because they are sins against the natural order, and sins against the 6th commandment. They may not necessarily be mortal sins (that depends upon the personal culpability of the one committing the sin, i.e. how guilty they are of it, to put it one way–i.e. whether they did the act freely and in the knowledge that it was grave), but they are still serious matters because they go against God’s plan and design for our sexuality. Through male and female complimentarity and our sexuality, God has given us a share in his creative power, and commanded us to be fruitful and multiply. Sexual sin reduces this very powerful and great gift from God to a mere recreational activity, selfishly undertaken for pleasure. That’s why it’s such a serious thing.


Corinthians 6:9-10… for just one example.

One could point to many places, St Paul (for example) in 1 Corinthians 6:9-10 says

Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.

A “fornicator” is someone who has sex outside of marriage.

Jesus Himself says in Matthew 19:

Have ye not read, that he which made them at the beginning made them male and female, And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh?

Clearly situating becoming one flesh (which happens physically during sex) within the context of marriage.

You might ask her where in the Bible she finds support for the idea that we ought to have sex outside of marriage

Also, if your friend says that we can live a sinful lifestyle and Jesus will change us, ask where that is in the Bible. The Bible indicates quite the opposite–Jesus gives us a fairly clear moral teaching in the Beatitudes and in the injunction to follow the commandments, and this is taken up by the subsequent teaching of Paul and the other NT authors. Revelation also describes some particularly interesting things that happen to people who don’t follow Jesus–he changes them alright, but that doesn’t mean it’s to something they’d probably enjoy, and it’s certainly not to someone in heaven…


I’d say she is conveniently overlooking both the law and the spirit of the law there to justify carnal sins. Even though you’re not exactly sure of it, your conscience is correct on this matter. People under a false “once saved always saved” doctrine have very little reason to resist temptation.

A person with a mature and godly view of sexuality understands that the place for sexual unity is within the marriage, and knows there is much more to being attractive to a spouse (and potential spouse) than what people do with their bodies. She has the concept backwards, but that is not anything new OR rare. Secular society tells her her idea is good, fine, sensible even. For her to put secular society’s words into God’s mouth, though, is wrong. Scripture and the Church are clear on the ordering of things and hers is backwards.

Congrats for knowing what she’s saying doesn’t sound right. I hope you get a far better answer than mine!

At the end of the day, we’re called to have self control over our bodies. Sexual sin is one of those self-control sins that people commit where 99% of the time it’s easy to say yes or no to. If you’re angry and start yelling at someone, typically it’s spur of the moment and it may not even cross your mind that you’re going to yell at the person. Sometimes even violent acts can occur so quickly that you don’t have a chance to stop yourself. Sex isn’t like that. You may start getting hot and heavy with someone (or yourself), but there’s plenty of time for you to realize what you’re doing and stop.

Taking that into consideration with the fact that we’re called to leave sex within the marital bond and you get the issue of sin.

So what about all the extremely high percentage of people who fornicate these days (including Catholics)? Well, if you find yourself in sin, you repent and try to amend your life, right?

Well if you continue fornicating with random people, that doesn’t quite add up to amending your life. If you keep fornicating with one person, but have no intention of marrying, that doesn’t work either. If you keep fornicating with one person and you end up marrying, well you’re still committing mortal sin every time you do it, but at least you’re making an attempt to amend your life by joining with that person together in the sacrament. That doesn’t excuse the act, but it shows progress to eliminating the sin.

You can apply this to any of the sexual sins. Adultery? Well stop doing it, repent and repair your sexual life (if possible) with your spouse.

Masturbation? Stop doing it. If you keep doing it, then try to slowly wane yourself off it. That doesn’t mean if you keep doing it you aren’t committing a mortal sin, but at least there’s intention to amend your life.

I think that intention is very important when dealing with sin.

There are “carnal” types,who really like sex ,and who wil make sure that they find someone to relate to quite young,and get married ,but it has little if anything to do with respect,and love . Many modern women who wish to be loved and respected find it very difficult to find men on their level,and end up having sex ,just to have some company.

I think it is time the RCC (hopefully under pope Francis),will bring up the subject of how men have (yes mainly men ) who wanted virgins, have so badly ,broken the "covenant"between men and women,and for so long, that it is just not possible to go back,because it is so badly damaged . Men until recently had total control over society,and women ,and still in the Church, “run” things .
This habit of pointing at individuals as sinners,instead of as only a personal responsiblity will have to end . The spiritually blind set in motion, by their vile behaviour towards others whom they look down on and use,a whole traill of devastation,and they don’t see it.
One of these is the high abortion rate in the US,which is the most militarily armed country in the world,has been the greediest country ,without exception ,has set in motion the horrendous pornographic industry,and has forced the rest of the world to buy her goods,and cheap culture,and murdered millions of people for their oïl etc
You really think that, in comparison with these SINS that,2000 years later, God is as concerned about people going to Church to legitimise their union ,when they can do so before God Himself in their own home .
This is why Francis has said, stop your pointing at certain sins ,for there are even greater ones,and when they are fixed ,so can the rest be fixed
Until then !!! then talk to the men !!! teach them how to court women

I used to be in the “I am going to wait until marriage” camp to have sex. Thankfully, I did not meet up to that. I was pretty hardcore, and managed to go all throughout college without doing the deed. But, once I had sex, I realized how much of a big deal it ISN’T, and thought I was silly for waiting so long. I honestly have no idea why religion puts so much guilt and shame on sex. I think it really has an opposite effect because I ended up having LOTS of sex with LOTS of people because I was so repressed but then I felt guilty, and then felt worthless, then ended up having even more sex. I have taken the guilt out of sex and I feel much better about it. While I am more selective of who I have sex with now and much prefer being in a relationship, I would never marry someone without having sex with them. It’s like buying a car without test driving it. Sexual compatibility is not the MOST important thing in a relationship, but it is still pretty important. If you are not sexually satisfied with someone, you are going to want to seek sex elsewhere. And it’s only human nature to wonder what it’s like having sex with other people. I’ve had sex with several people so I’ve already gotten it out of my system.

So true. Especially, when someone is addicted to something wrong it is difficult to stop committing the sin directly , Intention is so important to stop sinning and the person should stop doing let’s say Masturbation slowly time after time until he can control himself and stop doing it at all.

Well let’s look at what the pill gave us since it became widely available.

There has been an explosion of sexually transmitted diseases, not only in how many people are now affected but in the types of diseases one can catch. AIDS gets a lot of publicity on how awful it is, but with this and the rest of STDs, if everyone started to live according to God’s law, get married and have sex with your partner, we would not have any of these diseases.

There has been an explosion of young women who are pregnant and don’t want to be. Then this brought on a demand for abortions. This is not God’s plan for young women and their children.

Because of contraception, young men seem to walk away from their pregnant girlfriends because they never intended to be with the young lady and have a family. Besides, it’s now her problem that can be dealt with with an abortion. Is this how we want our young men to be? They are far from being the pillars of their community, self-sacrificing, loving, and caring for women and children.

A huge amount of people living below the poverty line are single women with children. This is not God’s plan for them.

As outlined above, chastity before marriage, is good for families, good for our young men and women, good for children, good for the economy, and good for the country.

You don’t have to be a Christian to be able to see this. There is a reason why God set up marriage and family life like He did, and it’s a great plan. Too bad we think we know better, we all are suffering the consequences of sex outside of marriage.

God bless.

Yes the bigger question is why she thinks living sinful lives does not affect our salvation.

Ask her if one of her church members turned into hitler. Then would they be saved.

She will probably say no.

Then ask what the difference is between that and other sins. Do not all sins offend God? Then ask where she draws the line and why.

Hopefully that will at least get her to think on it more. I used to go to churches that were the same way. The theology is not well formulated.

What natural order? God created sex; man created marriage.

The 6th commandment prohibits adultery. Fornication and adultery are not the same thing.

For a simple, Catholic perspective, from the Catechism of the Catholic Church:

2351 Lust is disordered desire for or inordinate enjoyment of sexual pleasure. Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes.

2352 By masturbation is to be understood the deliberate stimulation of the genital organs in order to derive sexual pleasure. "Both the Magisterium of the Church, in the course of a constant tradition, and the moral sense of the faithful have been in no doubt and have firmly maintained that masturbation is an intrinsically and gravely disordered action."138 “The deliberate use of the sexual faculty, for whatever reason, outside of marriage is essentially contrary to its purpose.” For here sexual pleasure is sought outside of "the sexual relationship which is demanded by the moral order and in which the total meaning of mutual self-giving and human procreation in the context of true love is achieved."139

To form an equitable judgment about the subjects’ moral responsibility and to guide pastoral action, one must take into account the affective immaturity, force of acquired habit, conditions of anxiety or other psychological or social factors that lessen, if not even reduce to a minimum, moral culpability.

2353 Fornication is carnal union between an unmarried man and an unmarried woman. It is gravely contrary to the dignity of persons and of human sexuality which is naturally ordered to the good of spouses and the generation and education of children. Moreover, it is a grave scandal when there is corruption of the young.

2354 Pornography consists in removing real or simulated sexual acts from the intimacy of the partners, in order to display them deliberately to third parties. It offends against chastity because it perverts the conjugal act, the intimate giving of spouses to each other. It does grave injury to the dignity of its participants (actors, vendors, the public), since each one becomes an object of base pleasure and illicit profit for others. It immerses all who are involved in the illusion of a fantasy world. It is a grave offense. Civil authorities should prevent the production and distribution of pornographic materials.

(See more here:

Here’s an article on the subject from Catholic Answers:

And, here’s a question on the subject written by Father Vincent Serpa:

Who actually wrote the Catechism? And by what authority?

The same institution which compiled the Bible and by the same authority…

And what institution is that?

By the church. By the authority of Christ

I’m looking for names; not just The Church.

And where is it written that Christ commissioned “The Church” to make up all these rules about sex? (Specifics, please).

If you open the catechism you will find tons of footnotes from many saints and popes and Bishops of the church. It is written by many people, compiled by the Bishops. This all comes from the authority given the church in Matt 16:18, Matt 18, Matt 25 and John 20 among other places.

Perhaps you can be more specific on which sexual sins you oppose.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit