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.

293. The Lord came into the world to save the human race, which otherwise would have suffered eternal death. He saved it by gaining control over the hells, which were assaulting everyone who entered this world and everyone who left it. He also saved the human race by glorifying his own human nature, because this gave him the power to keep the hells under his control forever.

His gaining control over the hells and the simultaneous glorification of his human nature were effected by allowing the human nature that he received from his mother to undergo spiritual crises and by continuous victories in those crises. His suffering on the cross was his last spiritual crisis; in it he made his victory complete.