I will sing of the mercies of the Lord for ever
Both temporal and spiritual, especially the latter, in which there is a large display of the rich and abundant mercy of God, from whence they are so called; as in the choice of men to everlasting life, who are said to be vessels of mercy; in the covenant of grace made with them, the blessings of which are the sure mercies of David; in the mission of Christ, whose coming, as the dayspring from on high, is owing to the tender mercy of our God; in redemption by him, in which mercy and truth have met together; in regeneration, which is according to abundant mercy; in the forgiveness of sins, which is according to the multitude of his tender mercies; and in the whole of salvation, which is not by works of righteousness, but by the mercy of God through Christ: the word may be rendered "graces, kindnesses, goodnesses" F12, and designs the abundance of grace; as in the heart of God, in the covenant, in the hands of Christ, as displayed through him, and in the several parts of salvation, and the whole of it: and these are a proper subject for a song; and a truly gracious soul, sensible of these things, thankful for them, cheerful on account of them, and seeing his interest in them, cannot but "sing" of them; and will determine to do it "for ever", every day, and all the day long, as long as he lives, and while he has any being, and which he will do to all eternity:
with my mouth will I make known thy faithfulness to all generations;
God is faithful to himself, to all the perfections of his nature, to his truth, holiness, and justice, he cannot deny himself; he is so to his Son, and to all engagements with him, and promises to him; to all his counsels, purposes, and decrees; all which are faithfulness and truth, or faithfully and truly performed; and to his covenant and promises made to his people in Christ, in whom they are all yea and amen: and that this glorious perfection of God might be made known to the saints in all successive generations, and be taken notice of by them, the psalmist spoke and sung this psalm with his mouth, and penned it with his hand; in which there is more mention made of the faithfulness of God than perhaps in any other passage of Scripture besides; see ( Psalms 89:2 Psalms 89:5 Psalms 89:8 Psalms 89:24 Psalms 89:33 ) .