(All Church Father quotes are from the Catena Aurea on Matthew 25.)
a) What is the Message behind the Parable?
As Jesus himself said, “Watch, therefore, for you know neither the day nor the hour.” Also, St. Jerome offers this wisdom: “seeing we know not the day of judgment, we should be careful in providing the light of good works.”
We do not know when the Lord will return, and when he does, it will be too late for us to make up what is lacking in ourselves. The righteous who will enter the kingdom cannot supply for the unrighteous who are left outside… not because they don’t want to, but because they cannot:
“None of us shall be able in that day to stand forth as patron of those who are betrayed by their own works, not because he will not, because he cannot.” (St. Chrysostom)
“Each man shall receive the recompense of his own works, and the virtues of one cannot atone for the vices of another in the day of judgment.” (St. Jerome)
“No man is profited in God’s sight by the testimony of others, because God sees the heart, and each man is scarce able to give testimony concerning his own conscience.” (St. Augustine)
It is important, in this regard, to make it clear that this parable does not speak of our particular judgment and purgatory (wherein the suffrages of the living do benefit the righteous dead who are being purified), but rather the general judgment; for example, the parable deals with groups of people, even though said groups (of five) can be allegorized into representing the “complete” person: each group represents all five of our senses, directed either to the heavenly (wise) or the earthly (foolish), as interpreted by St. Gregory the Confessor, St. Jerome, and St. Augustine.
And, as for why it is better that we know not when the Lord will return: “If, now that we know not the end, we are careless, what would we do if we knew it? We would keep on our wickednesses even to the end.” (St. Theophilus)
b) What doctrines do we see being taught in each Parable?
I think, when we come to understand what is represented by the lamps and oil. Church Father commentary paints a pretty consistent picture, that the lamps are our faith, and the oil represents our [gasp!] good works. St. Augustine supports thus notion with Matthew 5:16: our light must shine before others that they may see our good works.
Faith in Jesus Christ is not enough to grant us entrance into the Kingdom of Heaven when the Lord returns. The foolish maidens knew the bridegroom, but that was not sufficient for them. In the words of St. Jerome: “After the day of judgment, there is no more opportunity for good works.” and “What avails it to confess with the mouth Him whom you deny with your works?”
c) Can a Parable be used to defend against Non-Catholic doctrines?
This parable speaks against “faith alone” and “once saved, always saved”. (Matthew 25 is a most “Catholic” chapter of that gospel.)
d) What is the context of the Parable?
This parable describes the kingdom of heaven and those who are awaiting the Lord’s return. The first verse of this parable starts with the word “then”, implying a certain time, and one that he has just told his disciples about.
The context, then, is found in Matthew 24: Jesus is speaking to his disciples privately, and they ask him “what will be the sign of your coming and of the close of the age?” (Matthew 24:3) Jesus tells them of signs, and of the suddenness of his return. He has just told them the parable of the faithful and unfaithful servants (from Luke 12:42-48), which is focused on the behavior of the servants in the household, especially at the time of the master’s return. Therefore, the “Then…” in this parable refers to the second coming.