Psalms 89:37

Overview - Psalms 89
The psalmist praises God for his covenant;
for his wonderful power;
15 for the care of his church;
19 for his favour to the kingdom of David.
38 Then complaining of contrary events,
46 he expostulates, prays, and blesses God.
Treasury of Scripture Knowledge

Psalms 89:37  (King James Version)
It shall be established for ever as the moon, and as a faithful witness in heaven. Selah.

It shall
That is, as long as the sun and moon shall endure, as long as time shall last, his kingdom shall continue among men. The moon is probably termed a faithful witness, because by her, particularly, time is measured. Her decrease and increase are especially observed by every nation; and by these time is generally estimated, especially among eastern nations:--So many moons is a man old--so many moons since such an event happened; and even their years are reckoned by lunations. Or, the rainbow may be intended; that faithful sign which God has established in the clouds, that the earth shall no more be destroyed by water.

72:7 104:19 Genesis 1:14-18 ; Jeremiah 31:35 Jeremiah 31:36

and as
Genesis 9:13-16 ; Isaiah 54:9 Isaiah 54:10