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.

1727. 'He brought out bread' means celestial things and the refreshment received from them, while 'and wine' means spiritual things and the refreshment received from them. This is clear from the meaning of 'bread' as that which is celestial, dealt with in 276, 680, and from the meaning of 'wine', and also of a vine and a vineyard, as that which is spiritual, dealt with in 1069, 1071. And because 'breed' means celestial things, and 'wine' spiritual, they were also made symbols in the Holy Supper. Here 'Melchizedek brought out bread and wine' has a similar meaning, for in the Ancient Church 'breed' was the representative of all celestial things, and 'wine' the representative of all spiritual things. Thus here they are representatives of the Lord Himself, the source of everything celestial and everything spiritual.