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.

1868. That these things are meant by these nations would take too long to confirm from the Word; nor is there any need to do so here as no more than their names are mentioned. Some of them have been dealt with already, for example that 'the Rephaim' means false persuasions, 567, 581, 1673; 'the Amorites' evils, 1680; 'the Canaanites' evils, above at verse 16; 'the Perizzites' falsities, 1574. What the rest of the nations mean individually will in the Lord's Divine mercy be explained as they occur later on.

[2] As regards the nations that were to be cast out of the Lord's kingdom, in the next life evil and devilish spirits like nothing more than to surface in the world of spirits and to infest good spirits. But as often as they do so they are cast out, in much the same way as the falsities and evils that have taken possession of one who is being regenerated are overpowered and dispersed, and in their place truths and goods are implanted that belong to the Lord's kingdom.

[3] These falsities and evils were represented by the nations that were driven out of the land of Canaan by the descendants of Jacob. They were represented as well by the Jews themselves who at a later period were driven out from there. The same occurred with many other nations of old by whom similar things had been represented, such as the Horites who were driven from Mount Seir by the descendants of Esau, mentioned in Deuteronomy 2:12, 22; then the Avim who were driven out by the Kaphtorim, mentioned in Deuteronomy 2:23; also the Emim or Rephaim who were driven out by the Moabites, mentioned in Deuteronomy 2:9-11; as well as the Zamzummim who were driven out by the Ammonites, mentioned in Deuteronomy 2:19-21; besides many others referred to in the Prophets.