Sing unto the Lord, O ye saints of his - This call upon others to give thanks to God is in view of the mercy which he had experienced. He invites them to unite with him in celebrating the praises of that God who had showed him so much mercy. It was not because they had been benefited by these tokens of the divine favor; but:
(a) because when we are partakers of the divine mercy, we desire that others may assist us in giving utterance to the praise due to God; and
(b) because others may learn from the mercies bestowed on us that God is worthy of praise, or may see in His dealings with us an argument for His goodness; and may, therefore, appropriately unite in His praise.
Thus religion diffuses its influence on all around us, and tends to “unite” the hearts of many in every manifestation of the character of God. Infidelity is solitary and dissocial; religion is social; and, no matter on whom the favor is bestowed, its effect is to unite the hearts of many to each other and to God.
And give thanks at the remembrance of his holiness - Margin, “to the memorial.” The Hebrew is, “to the memory of his holiness.” The sense is, in calling to recollection the acts of his holiness, or his holy perfections. Compare the notes at Psalms 22:3. The word “holiness” here is used in a large sense as denoting, not so much the hatred of sin, as benevolence, kindness, mercy - the divine compassion toward those who are in trouble or danger. It is true that it is a proper subject of rejoicing and praise that God is a holy God, a God of truth and justice, a God who cannot look upon sin but with abhorrence, a God in whose nature is combined every possible perfection; but that is not the exact idea here. The word refers to his compassion, goodness, kindness; and to the acts by which that had been manifested to the psalmist, as laying a proper foundation for gratitude and praise.