ANSWER: Your question about the parable of the virgins and buying more oil correlates to Proverbs 23:23, which states we should BUY the truth and wisdom. The scriptures regarding your inquiry are in the book of Matthew, chapter 25.
1. "Then shall the kingdom of heaven be compared to (a parable is a story that uses something KNOWN to reveal something UNKNOWN) ten virgins, who took their lamps and went out to meet the bridegroom. 2. And five of them were wise, and five were foolish. 3. The ones who were foolish took their lamps, but they did not take oil with them; 4. But the wise took oil in their vessels along with their lamps.
7. Then all those virgins arose and trimmed their lamps. 8. And the foolish said to the wise, 'Give us some of your oil, because our lamps are going out.' 9. But the wise answered, saying, 'No, lest there not be enough for us and for you. But instead, go to those who sell, and buy for yourselves.' (Matthew 25:1 - 4, 7 - 9, HBFV throughout)
In order to answer your question, we need to consider what causes five of the ten virgins to lack enough oil in their lamps. What does the "oil" here represent? Is it truth, wisdom, instruction, and understanding themselves? Does it mean that God can impart spiritual wisdom and truth to people's minds?
All the virgins in the parable represent truly converted people that exist before Jesus' second coming. They are not those who do not have a relationship with God. What, then, keeps five of them out of God's kingdom? It was not the lack of spiritual wisdom or knowledge per se, but the lack of the Holy Spirit, which imparts spiritual wisdom and knowledge to believers.
At least two Biblical verses correlate physical oil with the Holy Spirit. Consider first Isaiah 61:1, which Jesus later referred to concerning his fulfilling of it by His ministry (Luke 4:18, 20).
1. The Spirit of the Lord GOD is upon Me because the LORD has anointed Me to preach the Gospel to the poor; He has sent Me to bind up the broken hearted, to proclaim liberty to the captives, and the opening of the prison to those who are bound; (Isaiah 61:1)
Notice how the oil for formally appointing a king of Israel is functionally equated with the Spirit of the Lord. This relates to the fact that the title "Messiah" or "Christ" means "The Anointed One." Although Jesus had had the Holy Spirit from the time He was conceived in the Virgin Mary's womb (cf. Luke 1:35, 41), he also received the Holy Spirit after being publicly baptized (Luke 4:21 - 22), which is how He became anointed. Likewise, consider what happened right after Samuel anointed David king of Israel.
13. And Samuel took the horn of oil and anointed him in the midst of his brothers. And the Spirit of the LORD came upon David from that day forward. And Samuel rose up and went to Ramah (1Samuel 16:13)
In this light, the five virgins who did not enter the kingdom ran low on the Spirit (i.e., the metaphorical "oil" in their lamps), which is the means by which they receive spiritual knowledge and wisdom from the Eternal. Paul makes this function of the Holy Spirit clear in 1Corinthians chapter 2.
In conclusion, based on this general analysis, shortly before Christ's return, the Parable of the Ten Virgins says there will be Christians who are so slack in their spiritual duties that they will not have enough of the Holy Spirit in order to endure to the end (Matthew 24:13). This means all true Christians should make sure they have the faith and are diligent enough in their spiritual lives not to be caught unprepared when the Lord returns (Matthew 24:45 - 51). It is a believer's duty not to become one of the spiritually foolish virgins.
Written by Eric Snow
A BibleStudy.org Email Evangelist