John Calvin Commentary 2 Peter 1:2

"Grace to you and peace be multiplied in the knowledge of God and of Jesus our Lord;" — 2 Peter 1:2 (ASV)

Grace and peace. By grace, God’s paternal favor towards us is designated. We have indeed been reconciled to God once for all by the death of Christ, and by faith we come to possess this great benefit; but as we perceive God’s grace according to the measure of our faith, it is said to increase according to our perception when it becomes more fully known to us.

Peace is added; for as our happiness begins when God receives us into His favor, so the more He confirms His love in our hearts, the richer the blessing He confers on us, so that we become happy and prosperous in all things.

Through the knowledge, literally, in the knowledge; but the preposition ἐν often means “through” or “with”; yet both senses may suit the context. I am, however, more disposed to adopt the former.

For the more anyone advances in the knowledge of God, every kind of blessing increases also equally with the sense of divine love. Whoever then aspires to the full fruition of the blessed life that Peter mentions must remember to observe the right way. He connects together at the same time the knowledge of God and of Christ, because God cannot be rightly known except in Christ, according to that saying:

No one knows the Father but the Son, and he to whom the Son will reveal Him (Matthew 11:27).