Sun-faced Buddha and Moon-faced Buddha are metaphors used in Buddhism. The Sun-faced Buddha lives in the world for a long period – 1800 years or for eternity, the Moon- faced just for one day.
When we think about our human lives:
There are, as you know, people who live long, like those Sun-faced Buddhas, and there are people whose lives are short, like those Moon-faced Buddhas.
It’s useless to worry.
Baso Dōitsu 709 – 788 recorded in The Blue Cliff Record, a collection of Chan Buddhist koans compiled in 1125