In the parable of the ten virgins, I have often wondered if the master's respone, "I know ye not" was a little bit harsh. As I read it this time, I looked up a cross-reference in the Book of Mormon in Mosiah 26:24-28. It describes the Second Coming and says that, at the second trump, "then shall they that never knew me come forth and shall stand before me." Already I started to see the situation in a different light. These people never knew him; this new perspective was different that they idea that He just didn't know them. Verse 26 of Mosiah continues: "Then shall they know that I am the Lord their God, that I am their Redeemer; but they would not be redeemed." The master didn't know the foolish virgins not because he didn't put forth the effort, but because they weren't ready to accept him as the master when he came.
Within the parable, we can implicitly infer that the foolish virgins didn't bring any oil at all. They had some, but only what was in their lamps (if their lamps had gone out, it must have meant that there was originally oil there). But the wise virgins "took oil in their vessels with their lamps." By having this extra oil, they were ready when the bridegroom came and he knew them.
What can this extra oil in the vessels represent? I believe it is the Atonement of Christ, the blessings of which we must be willing to receive. In 2 Nephi 25:23 it tells us "that it is by grace that we are saved, after all we can do." How often do we stop at the step of doing all that we can and forget to apply the grace of God? We forget to receive the gift. We have some preparation, the oil in our lamps, but we forget to use the power of the Atonement, the oil in our vessels. Think of the best we've ever done- now think how much better it could be with the power of Christ's Atonement augmenting it! We can't just have the oil of our own efforts- we need the Atonement to help us.