William Burkitt on 2 Peter 1:2

The person saluting, and the parties saluted, were mentioned in the former verse; here we have the salutation itself, 1. The matter of it, Grace and peace; grace to free us from God's wrath, and reinstate us in his favour; peace to quiet our own consciences, and reconcile us to ourselves.

Observe,2. The measure of it, grace and peace be multiplied; they had both grace and peace already, yet the apostle prays for the farther increase of them; there is no complete perfection in grace attainable in this life. The best of saints must be multiplying and increasing their stores; for they are but imperfectly perfect, when at the best.

Observe, 3. The means for multiplying grace and peace, through the knowledge of God, and of Jesus Christ our Lord.

Learn, That the knowledge of God, in, by, and through our Lord Jesus Christ, is the special mean of multiplying grace and peace in our hearts; and indeed there is no comfortable knowledge of God, but in and through Christ, This is life eternal, &c. John 17:3. Out of Christ God is a revenger, in Christ a reconciled Father.