30 And now come words in perfect harmony with the inward assurance of our faith. He says, And they shall bless the true God, and they that swear upon earth shall swear by the true God. And indeed they who in God's service have received the new name shall bless God; and moreover the God by Whom they shall swear is the true God. What doubt is there as to Who this true God is, by Whom men shall swear and Whom they shall bless, through Whom a new and blessed name shall be given to them that serve Him? I have on my side, in opposition to the blasphemous misrepresentations of heresy, the clear and definite evidence of the Church's faith; the witness of the new name which Thou, O Christ, hast given, of the blessed title which You have bestowed in reward of loyal service. It swears that You are true God. Every mouth, O Christ, of them that believe tells that You are God. The faith of all believers swears that You are God, confesses, proclaims, is inwardly assured, that You are true God.
Source: On the Trinity (New Advent)