First, as we read in Psalm 119:105 the word of God is the lamp. “Your word is a lamp for my feet, a light on my path.” So if anyone has a Bible, they have a lamp.
What is the oil in the parable of the ten virgins? There is more understanding about the parable of the ten virgins when it talks about oil from the book of Hebrews. Oil wasn’t brought by the foolish virgins. In Hebrews 1:9 it says that oil is the “oil of gladness.” “You have loved righteousness and hated lawlessness; Therefore God, Your God, has anointed You With the oil of gladness more than Your companions.””
Hebrews 1:9 NKJV
The verse also says “more than your companions.” I think this could mean the wise virgins had in their company the foolish virgins and God have them gladness more than the foolish ones. I think it means that the foolish virgins had no gladness. They followed without any oil of gladness. How do we get oil of gladness, by “hating lawlessness and loving righteousness.” Sin is lawlessness. So because we hate sin, we get the oil of joy. And we have to remember to be glad and take the oil of gladness with us. We purchase this by coming to Jesus and putting our faith in Him and live like he wants us to.
This means we need to live righteously by doing the will of God and God will give us this oil. This is just one interpretation of the oil. The oil is often looked at as the Holy Spirit but I just wanted to give another interpretation. Thank you.