Charles H. Spurgeon on Psalms 69:5

O God, thou knowest my foolishness. David might well say this, but not David's Lord; unless it be understood as an appeal to God as to his freedom from the folly which men imputed to him when they said he was mad. That which was foolishness to men was superlative wisdom before God. How often might we use these words in their natural sense, and if we were not such fools as to be blind to our own folly, this confession would be frequently on our lips. When we feel that we have been foolish we are not, therefore, to cease from prayer, but rather to be more eager and fervent in it. Fools had good need consult with the infinitely wise. And my sins are not hid from thee. They cannot be hid with any fig leaves of mine; only the covering which thou wilt bring me can conceal their nakedness and mine. It ought to render confession easy, when we are assured that all is known already. That prayer which has no confession in it may please a Pharisee's pride, but will never bring down justification. They who have never seen their sins in the light of God's omniscience are quite unable to appeal to that omniscience in proof of their piety. He who can say, Thou knowest my foolishness, is the only man who can add, "But thou knowest that I love thee."