He shall abide before God forever: O prepare mercy and truth, which may preserve him.
Read Chapter 61
Augustine of Hippo
AD 430
8. "He shall abide for everlasting in the sight of God" (ver. 7); according to what, or because of what? "His mercy and truth who shall seek for Him?" He saith also in another place, "All the ways of the Lord are mercy and truth, to men seeking His testament and His testimonies." Large is the discourse of truth and mercy, but shortness we have promised. Briefly hear ye what is truth and mercy: because no small thing is that which hath been said, "All the ways of the Lord are mercy and truth." Mercy is spoken of, because our merits God regarded not, but His own goodness, in order that He might forgive us all our sins, and might promise life everlasting: but truth is spoken of, because He faileth not to render those things which He hath promised. Let us acknowledge it here, and let us do it; so that, just as to us God hath shown forth His mercy and His truth, mercy in forgiving our sins, truth in showing forth His promises; so also, I say, let us execute mercy and truth, mercy concerning...
Search? Who can comprehend what thou hast prepared for this king? He may allude to the promises made to David's family, (Psalm lxxxviii. 30, 38.; Calmet) which should reign for ever, by means of Christ. (Haydock)
Who can explain the mercy of God in redeeming us; and his fidelity in granting his promised rewards? (Worthington)