Now what follows is spoken in the person of The Crucified. For from the head of this Psalm are the words, which He cried out, whilst hanging on the Cross, sustaining also the person of the old man, whose morality He bare. For our old man was nailed together with Him to the Cross.
2. “O God, my God, look upon me, why hast Thou forsaken me far from my salvation?” (ver. I). Far removed from my salvation: for “salvation is far from sinners” (Psalm 119:155). “The words of my sins.” For these are not the words of righteousness, but of my sins. For it is the old man nailed to the Cross that speaks, ignorant even of the reason why God hath forsaken him: or else it may be thus, The words of my sins are far from my salvation.
3. “My God, I will cry unto Thee in the daytime, and Thou wilt not hear” (ver. 2). My God, I will cry unto Thee in the prosperous circumstances of this life, that they be not changed; and Thou wilt not hear, because I shall cry unto Thee in the words of my sins. “And in the night-season, and not to my folly.” And so in the adversities of this life I will cry to Thee for prosperity; and in the manner Thou wilt not hear. And this Thou doest not to my folly, but rather that I may have wisdom to know what Thou wouldest have me cry for, not with the words of sins out of longing for life temporal, but with the words of turning to Thee for life eternal.
From Nicene and Post-Nicene Fathers, vol. 8: Augustine, Expositions on the Psalms (XXII, 2-3). ed. Philip Schaff (p. 58)