Sing unto the LORD, O you saints of his, and give thanks at the remembrance of his holiness.
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Augustine of Hippo
5. "Sing to the Lord, O ye saints of His." The prophet seeing these future things, rejoiceth, and saith, "Sing to the Lord, O ye saints of His. And make confession of the remembrance of His holiness" (ver. 4). And make confession to Him, that He hath not forgotten the sanctification, wherewith He hath sanctified you, although all this intermediate period belong to your desires.
Saints. Hebrew, "who have obtained mercy. "Priests and faithful people come to return thanks, because God has turned away the scourge. (Calmet)
Memory, or name, Exodus iii. 15. (Calmet)
It is from God, and not from ourselves, that holiness comes. (Worthington)