Irenaeus

Now, that this God is the Father of our Lord Jesus Christ, Paul the apostle also has declared, [saying,] "There is one God, the Father, who is above all, and through all things, and in us all." I have indeed proved already that there is only one God; but I shall further demonstrate this from the apostles themselves, and from the discourses of the Lord. For what sort of conduct would it be, were we to forsake the utterances of the prophets, of the Lord, and of the apostles, that we might give heed to these persons, who speak not a word of sense?