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.

'A lamp' signifies truths of faith. It can also signifying celestial things from which spiritual matters proceed. 'A lamp' or 'candle' signifies intelligence in both senses.

In Matthew 25:4, this signifies love.

The 'ordination of the lamp, from the evening until the morning,' as in Exodus 27:20, 21, signifies the perpetual influx of the good and truth from the Lord always in every state. Its light signifies illumination from the Lord.

In Revelation 22, this signifies natural light from self-derived intelligence.

(Odkazy: Apocalypse Revealed 796)