The Refutation of All Heresies: Book X. 24Noetus and Callistus.

But in like manner, also, Noetus, being by birth a native of Smyrna, and a fellow addicted to reckless babbling, as well as crafty withal, introduced (among us) this heresy which originated from one Epigonus. It reached Rome, and was adopted by Cleomenes, and so has continued to this day among his successors. Noetus asserts that there is one Father and God of the universe, and that He made all things, and was imperceptible to those that exist when He might so desire. Noetus maintained that the Father then appeared when He wished; and He is invisible when He is not seen, but visible when He is seen. And this heretic also alleges that the Father is unbegotten when He is not generated, but begotten when He is born of a virgin; as also that He is not subject to suffering, and is immortal when He does not suffer or die. When, however, His passion came upon Him, Noetus allows that the Father suffers and dies. And the Noetians suppose that this Father Himself is called Son, (and vice versa,) in reference to the events which at their own proper periods happen to them severally.

Callistus corroborated the heresy of these Noetians, but we have already carefully explained the details of his life. And Callistus himself produced likewise a heresy, and derived its starting-points from these Noetians,--namely, so far as he acknowledges that there is one Father and God, viz., the Creator of the universe, and that this (God) is spoken of, and called by the name of Son, yet that in substance He is one Spirit. For Spirit, as the Deity, is, he says, not any being different from the Logos, or the Logos from the Deity; therefore this one person, (according to Callistus,) is divided nominally, but substantially not so. He supposes this one Logos to be God, and affirms that there was in the case of the Word an incarnation. And he is disposed (to maintain), that He who was seen in the flesh and was crucified is Son, but that the Father it is who dwells in Him. Callistus thus at one time branches off into the opinion of Noetus, but at another into that of Theodotus, and holds no sure doctrine. These, then, are the opinions of Callistus.