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.

1514. Spheres are also made perceptible to the senses by means of odors, which spirits smell far more keenly than men do; for, remarkably, odors correspond to spheres. With people who have given themselves up to the practice of deceit and have as a consequence acquired a deceitful disposition, there is a stink of vomit when their sphere is converted into an odor. With those who have studied how to speak eloquently so that it may all lead to self-admiration, their sphere when converted into something odoriferous is like the smell of burnt bread. With those who have given themselves up to the pursuit of mere pleasure and with whom no charity or faith has existed, the odor of their sphere is that of excrement. It is similar in the case of those who have gone through life committing adultery, whose odor is even more obnoxious. With those who have led lives of intense hatred, of revenge, and of practicing cruelty their sphere, when converted into odors, is the stench of a corpse. From those who have been disgustingly avaricious the stench of mice is given off, and the stench of house-lice or bugs comes from those who persecute the innocent. These odors cannot be detected by anyone unless his interior senses have been opened in such a way that he is at the same time in the company of spirits.