"Let us observe, in this song of praise,
I. How David adores God, and gives him the glory of his infinite perfections. There is none like him, nor any to be compared with him (For who is God, save the Lord? and who is a rock, save our God ? verse 32) All others that are adored as deities are counterfeits and pretenders. None is to be relied on but he. Who is a rock, save our God? They are dead, but the Lord liveth. They disappoint their worshipers when they most need them. But as for God his way is perfect, (verse. 31). Men begin in kindness, but end not,-promise, but perform not; but God will finish his work, and his word is tried, and what we may trust.
II. How he triumphs in the interest he has in this God, and his relation to him, which he lays down as the foundation of all the benefits he has received from him: He is my God; as such he cries to him (In my distress I called upon the Lord, and cried to my God: and he did hear my voice out of his temple, and my cry did enter into his ears. Verse 31), and cleaves to him (For I have kept the ways of the Lord, and have not wickedly departed from my God. Verse 22 ); "and, if my God, then my rock" (verse 2), that is, "my strength and my power (verse 33), the rock under which I take shelter (he who is to me as the shadow of a great rock in a weary land), the rock on which I build my hope,"( verse 3). Whatever is my strength and support, it is the God of my rock that makes it so; nay, he is the God of the rock of my salvation (verse 47): my saving strength is in him and from him. David often hid himself in a rock (1 Sam. xxiv. 2), but God was his chief hiding-place. "He is my fortress, in which I am safe and think myself so—my high tower, or stronghold, in which I am out of the reach of real evils—the tower of salvation (verse 51), which can never be sealed nor battered, nor undermined. Salvation itself saves me. Am I in distress? he is my deliverer—struck at, shot at? he is my shield—pursued? he is my refuge—oppressed? He is my Savior, that rescues me out of the hand of those that seek my ruin. "Am I burdened, and ready to sink? The Lord is my stay (verse 19), by whom I am supported. Am I in the dark, benighted, at a loss? Thou art my lamp, O Lord! to show me my way, and thou wilt dispel my darkness," (For thou art my lamp, O Lord: and the Lord will lighten my darkness. ( verse 29). If we sincerely take the Lord for our God, all this, and much more, he will be to us, all we need and can desire."
~ Matthew Henry