Behold here, 1. A double blessing promised and insured, namely, justification and sanctification, forgiveness of sin, and cleansing from it, yea, from all iniquity; when God pardons sin, no sin is left unpardoned; the sea can as easily drown a thousand men as a single man; God's act of pardoning grace is free and full.
Observe, 2. The certainty of the mercy promised, God is faithful and just to forgive: not merciful and gracious, though so he is in himself, but faithful with respect to his promise to us, and just with respect to the satisfaction given by Christ for us. Almighty God in pardoning sin performs an act of strict justice with respect to Christ, as well as an act of grace and mercy, in regard of us; he is faithful and just, as well as gracious and merciful.
Observe, 3. The indispensible duty required on our part, and that is confession of sin, If we confess. Now confession of sin is a penitent sinner's voluntary accusing himself to God, and condemning himself before God, with hatred of, shame and sorrow for, and a full resolution against his sin, together with an earnest desire of, and some good hope in divine mercy.
Observe, 4. What relation confession stands in to remission, not as a meritorious cause; satisfaction, not confession, merits pardon, but it is an exclusive condition; there is no remission without confession; God will not pardon without it: And it is an inclusive condition; God will, certainly will, forgive them that confess: There is not only a possibility or probability, but an infallible certainty of obtaining remission upon confession.