This question is related to the question: How do "once saved always saved" advocates explain the parable of the wise virgins?
Many of the answers explain that the foolish virgins never had oil, however one answer pointed out that the difference is they did not take extra oil in a vessel. "But the wise took oil in their vessels with their lamps" (Mathew 25:4)
It does appear their lamps were burning since both "trimmed their lamps" (Matt 25:7) and the foolish said to the wise "our lamps are gone out" (Matt 25:8).
If this is the case, and the foolish virgins had oil in the lamp but it ran out, what does the oil signify?