Oil
Oil -- typically olive oil -- symbolizes the good that comes from celestial love. Celestial love is love of the Lord, the highest and purest love we can have. The good of celestial love is the desire to be good springing from celestial love: Wanting to do the Lord's will because you love Him. That's not a state many reach, even in heaven, but it's a beautiful goal. This representation makes sense based on the idea that the sun -- the source of all natural light and heat, and thus all natural life -- represents the Lord, the source of all spiritual light, heat and life. Burning oil was the most pure fire available in Biblical times, thus the closest representation of the sun people could create.
1 Kings 2:36-46
36
The king sent and called for Shimei, and said to him, "Build yourself a house in Jerusalem, and dwell there, and don't go out from there anywhere.
37
For on the day you go out, and pass over the brook Kidron, know for certain that you shall surely die: your blood shall be on your own head."
38
Shimei said to the king, "The saying is good. As my lord the king has said, so will your servant do." Shimei lived in Jerusalem many days.
39
It happened at the end of three years, that two of the servants of Shimei ran away to Achish, son of Maacah, king of Gath. They told Shimei, saying, "Behold, your servants are in Gath."
40
Shimei arose, and saddled his donkey, and went to Gath to Achish, to seek his servants; and Shimei went, and brought his servants from Gath.
41
It was told Solomon that Shimei had gone from Jerusalem to Gath, and was come again.
42
The king sent and called for Shimei, and said to him, "Didn't I adjure you by Yahweh, and warn you, saying, 'Know for certain, that on the day you go out, and walk abroad any where, you shall surely die?' You said to me, 'The saying that I have heard is good.'
43
Why then have you not kept the oath of Yahweh, and the commandment that I have instructed you with?"
44
The king said moreover to Shimei, "You know all the wickedness which your heart is privy to, that you did to David my father. Therefore Yahweh shall return your wickedness on your own head.
45
But king Solomon shall be blessed, and the throne of David shall be established before Yahweh forever."
46
So the king commanded Benaiah the son of Jehoiada; and he went out, and fell on him, so that he died. The kingdom was established in the hand of Solomon.
