Charles H. Spurgeon on Psalms 65:3

Iniquities prevail against me. Others accuse and slander me, and in addition to my own sins rise up and would beset me to my confusion, were it not for the remembrance of the atonement which covers every one of my iniquities. Our sins would, but for grace, prevail against us in the court of divine justice, in the court of conscience, and in the battle of life. Unhappy is the man who despises these enemies, and worse still is he who counts them his friends! He is best instructed who knows their deadly power, and flees for refuge to him who pardons iniquity. As for our transgressions, thou shalt purge them away. Thou dost cover them all, for thou hast provided a covering propitiation, a mercyseat which wholly covers thy law. Note the word our, the faith of the one penitent who speaks for himself in the first clause, here embraces all the faithful in Zion; and he is so persuaded of the largeness of forgiving love that he leads all the saints to sing of the blessing. What a comfort that iniquities that prevail against us, do not prevail against God. They would keep us away from God, but he sweeps them away from before himself and us; they are too strong for us, but not for our Redeemer, who is mighty, yea, and almighty to save. It is worthy of note that as the priest washed in the laver before he sacrificed, so David leads us to obtain purification from sin before we enter upon the service of song. When we have washed our robes and made them white in his blood, then shall we acceptably sing, "Worthy is the Lamb that was slain."