'Oil' in the Bible

Samuel took a flask of oil, poured it on Saul's head, kissed him, and said, "The LORD has anointed you Commander-in-Chief over his inheritance, has he not?

The LORD told Samuel, "How long will you grieve over Saul, since I've rejected him from being king over Israel? Fill your horn with oil and go. I'm sending you to Jesse from Bethlehem because I've chosen for myself one of his sons as king."

Then Samuel took the horn of oil and anointed David in the presence of his brothers, and the Spirit of the LORD came on David from that day forward. Then Samuel got up and went to Ramah.