Psalms 89:37

It shall be established for ever as the moon, and [as] a faithful witness in heaven. Selah.

Ver. 37. It shall be established for ever as the moon] If his sons be good they shall shine as the sun in his strength, saith Kimchi; as, if they be not, yet they shall be as the moon that shineth, though for a time obscured or eclipsed. A fit resemblance, saith Ainsworth, of the throne or Church of Christ, which hath not always one face or appearance in the world, though it be perpetual. The Papists would have this moon always in the full; and if she show but little light to us they will not yield she is the moon. And yet, except in the eclipse, astronomers demonstrate that the moon hath at all times as much light as she hath in the full; but oftentimes a great part of the bright side is turned to heaven, and a lesser part to the earth: and so the Church is ever conspicuous to God's eye, though it appear not always so to us.

And as a faithful witness in heaven] As oft, then, as we see the sun and moon in heaven let us think of the constance of God's covenant, and the perpetuity of Christ's kingdom. By this "faithful witness" some understand the rainbow, Genesis 9:13,17 .