John Calvin on Galatians 1:3

3. Grace be to you and peace. This form of salutation, which occurred in the other epistles, has received an explanation, to which I still adhere. Paul wishes for the Galatians a state of friendship with God, and, along with it, all good things; for the favor of God is the source from which we derive every kind of prosperity. He presents both petitions to Christ, as well as to the Father; because without Christ neither grace, nor any real prosperity, can be obtained.