Psalms 89:37

(37) And as a faithful witness in heaven.—Rather, and there is a faithful witness in heaven, which the parallelism shows to be the moon, just mentioned. The moon (see Psalms 81:3) was to the Jews—as to the ancients generally—the “arbiter of festivals,” and the festivals were signs of the covenant, consequently that luminary might well be called “a witness in heaven.”