Maschil of Ethan the Ezrahite. Who this Ethan was is not certain. Kimchi takes him to be the same with Ethan the wise man, a grandson of Judah, 1Ki 4:31. But seeing he lived some hundreds of years before the times of David, it is not likely that he should be the writer of this psalm; for David is made mention of in it, which could not be, unless it can be thought to be by a spirit of prophecy; which indeed is the opinion of Doctor Lightfoot , who takes this Ethan to be the penman of this psalm; and who"from the promise, Ge 15:1 sings joyfully the deliverance (of Israel); that the raging of the Red sea should be ruled, Ps 89:9, and Rahab, or Egypt, should be broken in pieces, Ps 89:10, and that the people should hear the joyful sound of the law, Ps 89:15, and as for the name of David in it, this, he says, might be done prophetically; as Samuel is thought to be named by Moses, Ps 99:6, which psalm is held to be made by him; or else might be put into it, in later times, by some divine penman, endued with the same gift of prophecy, who might improve the ground work of this psalm laid by Ethan, and set it to an higher key; namely, that whereas he treated only of bodily deliverance from Egypt, it is wound up so high as to reach the spiritual delivery by Christ; and therefore David is often named, from whence he should come.'
'There was another Ethan, a singer, in David's time; and it is more probable that he is the person, who might live to the times of Rehoboam, and see the decline of David's family, and the revolt of the ten tribes from it; or perhaps it was one of this name who lived in the times of the Babylonish captivity, and saw the low estate that David's family were come into; to which agrees the latter part of this psalm; and, in order to comfort the people of God, he wrote this psalm, showing that the covenant and promises of God, made with David, nevertheless stood firm, and would be accomplished: the title of the Septuagint version calls him Etham the Israelite; and the Arabic version Nathan the Israelite: the Targum makes him to be Abraham, paraphrasing it"a good understanding, which was said by the hand of Abraham, that came from the east.'
'But whoever was the penman of this psalm, it is "maschil", an instructive psalm, a psalm causing to understand; it treats concerning the covenant of grace, and the promises of it; and concerning the mercy and faithfulness of God, in making and keeping the same; and concerning the Messiah and his seed, his church and people; and the stability and duration of all these: many passages in it are applied to the Messiah by Jewish writers, ancient and modern; and Ps 89:20 is manifestly referred to in Ac 13:22.
Ver. 1. 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" , 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 Ps 89:2.
Works, vol. i. p. 699, 700.