Tertullian

My preliminary remarks on the preceding epistle called me away from treating of its superscription, for I was sure that another opportunity would occur for considering the matter, it being of constant recurrence, and in the same form too, in every epistle. The point, then, is, that it is not (the usual) health which the apostle prescribes for those to whom he writes, but "grace and peace." I do not ask, indeed, what a destroyer of Judaism has to do with a formula which the Jews still use. For to this day they salute each other with the greeting of "peace," and formerly in their Scriptures they did the same. But I understand him by his practice plainly enough to have corroborated the declaration of the Creator: "How beautiful are the feet of them that bring glad tidings of good, who preach the gospel of peace!" For the herald of good, that is, of God's "grace" was well aware that along with it "peace" also was to be proclaimed. Now, when he announces these blessings as "from God the Father and the Lord Jesus," he uses titles that are common to both, and which are also adapted to the mystery of our faith; and I suppose it to be impossible accurately to determine what God is declared to be the Father and the Lord Jesus, unless (we consider) which of their accruing attributes are more suited to them severally. First, then, I assert that none other than the Creator and Sustainer of both man and the universe can be acknowledged as Father and Lord; next, that to the Father also the title of Lord accrues by reason of His power, and that the Son too receives the same through the Father; then that "grace and peace" are not only His who had them published, but His likewise to whom offence had been given. For neither does grace exist, except after offence; nor peace, except after war. Now, both the people (of Israel) by their transgression of His laws, and the whole race of mankind by their neglect of natural duty, had both sinned and rebelled against the Creator.