But I will declare for ever,.... These are not the words of the psalmist, but of Christ, who is all along speaking in the psalm; what he would declare is not expressed, and is to be supplied in sense thus; either that he would declare the wonderful works of God, Psa 75:1, so the Targum, his thoughts, mercies, and kindnesses to his people, as in Psa 55:5, or his judgments on his enemies, whom he shall pass sentence on, which will be for ever; or the name of the Lord, his purposes and decrees, his counsel and covenant, his mind and will, his Gospel and the truth of it: see Psa 22:22, I will sing praises to the God of Jacob; the covenant God of his people, Christ's God, and their God; of his singing praise to him, see Psa 22:22.