The psalmist’s prayer (39:8–14). Sobered by his reflection on the impermanence of human existence, the psalmist begins the more formal part of his prayer; in the opening words, he gets right back to basics. “What have I hoped for?” Was it wealth, success, victory over enemies, freedom from persecution, or things of that nature? No! When he got right down to his most fundamental aspirations in life, the palmist’s hopes and desires focused upon God himself. And the realization that his ultimate focus in life was God created a new issue for the psalmist; it was no longer his enemies who were a primary source of external vexation, but an awareness of his own transgressions which became a primary source of internal vexation. If life was so transitory, and if God was its principal goal and meaning, then it was vital that transgressions (or sin) be dealt with, lest they destroy the potential and meaning of existence. His failure to perceive this truth made him vulnerable in another sense; he claimed to be a man of faith, but his obsession with enemies and the trappings of mortal life had become such that even a fool could see he had missed the point of life (v 9b). The fool might not agree with this perspective on life, but could reproach him for the double standard by which he lived. So the psalmist becomes silent again (v 10); this time, it is not self-imposed restraint to stop himself from speaking sinful words, but the silence of perception, for he has seen how God has acted.

Peter C. Craigie and Marvin Tate, Psalms 1-50, Volume 19: Second Edition (Word Biblical Commentary), 309.