The author of [Psalm 73] is certainly struggling to hold onto his own faith in God's goodness: "But as for me, my feet had almost slipped; I had nearly lost my foothold. For I envied the arrogant when I saw the prosperity of the wicked" (vv. 2-3). When the wicked prosper, it is all too easy to interpret their prosperity as indicating a deficiency in God's goodness; it is all too easy to feel foolish about continuing to trust: "surely in vain have I kept my heart pure; in vain have I washed my hands in innocence" (v. 13). The psalm does not ultimately take this view, however, and it is designed to help others who read it and pray it likewise not to take this view. As we move toward its conclusion, we find that in the course of his prayer the psalmist had processed his doubts, and has arrived at a renewed confidence: "my flesh and my heart may fail, but God is the strength of my heart and my portion forever" (v. 26).
This kind of prayer, often referred to as a "lament psalm," is one of the ways of rightly relating to God in biblical faith. God is good, yet his goodness appears to be absent in human experience right now. What is to be done? The answer advocated in the lament psalms is neither to give up on the goodness of God nor to pretend that things are better than they are. In the lament psalms, we see honest confrontation of the fact that there is a gap between theology, on the one hand, and experience, on the other. This gap is brought to God in prayer, and trust is renewed in God's goodness through the process of prayer. The psalms of lament are, therefore, regarded in biblical faith as being just as important for right relating to God as the psalms of praise. In these compositions, lament and trust go together; they are not alternatives. The challenging circumstances of life are neither ignored nor taken as a reason for turning away from God. They are fully described before God, and they issue characteristically in the prayer of those who still trust in his goodness: "turn, O LORD, and deliver me; save me because of your unfailing love" (Psalm 6:4).- pp. 175-176, emphasis mine