'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.

(References: Apocalypse Revealed 796)