The bridegroom was late — and only half of them were ready for late.
Ten young women wait for the bridegroom so they can escort him, with lamps, to the wedding feast. Five bring spare oil; five bring only what is in the lamp. The bridegroom is delayed, they all doze off, and at midnight someone shouts that he is coming.
Jesus tells it near the end, on the Mount of Olives, in a run of teaching about waiting for his return.
Watch therefore, for you don't know the day nor the hour in which the Son of Man is coming.
Notice that all ten fall asleep. The difference between the wise and the foolish is not that some stayed awake — it is that some prepared for the possibility of a long wait. "Watch" here does not mean insomnia. It means being ready for a delay nobody knows the length of.
The wise ones' refusal to share their oil looks mean at first reading. But the parable is saying something about what cannot be transferred: one person's readiness cannot be lent to another at the last minute. Some things each person has to have for themselves.
The ending is hard — the shut door and the "I don't know you" — and it is meant to be. But the tone of the chapter is not threat; it is wedding. The picture Jesus chooses for his return is a feast, and the question is whether there will be light to go in by.
Walking with Jesus has a collection called The Parables of Jesus that takes them one a day — each with the question he was answering, a short reflection, a prayer, and one thing to carry into the day.
It is a one-time purchase, about five minutes a morning, and it never asks you to catch up on days you missed.