They introduce God as a Being unknown; they suppose Christ to be unbegotten; and as to the Spirit, they do not admit that He exists. Some of them say that the Son is a mere man, and that the Father, Son, and Holy Spirit are but the same person, and that the creation is the work of God, not by Christ, but by some other strange power.
Be on your guard, therefore, against such persons. And this will be the case with you if you are not puffed up, and continue in intimate union with Jesus Christ our God, and the bishop, and the enactments of the apostles. He that is within the altar is pure, but he that is without is not pure; that is, he who does anything apart from the bishop, and presbytery, and deacons, such a man is not pure in his conscience.
Ignatius of Antioch
Epistle to the Trallians
Chapter VI – VII