Albert Barnes Commentary Psalms 69:5

"O God, thou knowest my foolishness; And my sins are not hid from thee." — Psalms 69:5 (ASV)

O God, you know my foolishness — the errors and follies of my life. Though conscious of innocence in this particular case—feeling that his enemies hated him without cause and took what belonged to him, not to them—he was nevertheless aware that he was a sinner. He was willing to confess before God that, however upright he might be in his dealings with people, toward God, he was a sinful man.

From Him, he deserved all that had come upon him. Indeed, the very calamities that had been permitted to come upon him were proof to his own mind that he was a sinner. They served, as they were doubtless designed, to turn his mind to that fact and to humble him. The effect of calamities coming upon us, reminding us that we are sinners, is often referred to in the Psalms. See Psalms 38:2-4; Psalms 40:12.

And my sins are not hidden from you — Margin, “guiltiness.” The word used here always has the idea of “guilt” attached to it. The meaning is that God knew all his life. Therefore, however unjust the conduct of “men” toward him might be when they treated him as if he had wronged them, all that had occurred was right when considered as part of God’s dealings or as something God allowed to happen to him. This was because it was a proper expression of God’s displeasure with his sins.

We may feel that we have not wronged our fellow men. Yet, even the treatment we receive from them, however unjust from their perspective, can be regarded as deserved by us from God. It may be seen as proper on His part: an expression of His displeasure for our transgressions against Him and proof that we are sinners. Trial never comes to us from any source except as it is founded on the fact that we are sinners. Even when there is complete innocence toward our fellow men, God may use their passions to rebuke and discipline us for our sins toward Him.