“There are these four types of brightness. Which four? The brightness of the sun, the brightness of the moon, the brightness of fire, and the brightness of discernment. These are the four types of brightness. And of these four types of brightness, the foremost is the brightness of discernment.”
AN4.144: Obhāsa Sutta
Obhāsa Sutta: Brightness - translated by Thanissaro Bhikkhu
Translated by Thanissaro Bhikkhu. Source text via dhammatalks.org.