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.

9388. 'And built an altar under the mountain' means a representative sign of the Lord's Divine Human in respect of Divine Good from Him. This is clear from the meaning of 'an altar' as a representative sign of the Lord's Divine Human, dealt with in 921, 2777, 2811, 4489, and therefore the chief representative of worship of the Lord, 4541, 8935, 8940; and from the meaning of 'the mountain' as the good of love, dealt with in 4210, 6435, 8327, 8658, 8758, in this instance the Divine Good of love which emanates from the Lord, since it was Mount Sinai, where the Lord was then. 'Mount Sinai' means Divine Good united to Divine Truth emanating from the Lord, see 8805.