sn.1.26 Saṁyutta Nikāya (Linked Discourses)

“How many sources of light are in the world
By means of which the world is illumined?
We have come to ask the Blessed One this:
How are we to understand it?”

“There are four sources of light in the world;
A fifth one is not found here.
The sun shines by day,
The moon glows at night,
And fire flares up here and there
Both by day and at night.
But the Buddha is the best of those that shine:
He is the light unsurpassed.”