Irenaeus on Theosis

If anyone swear by Tash and keep their oath for the oath’s sake, it is by me that they have truly sworn, though they know it not, and it is I who reward them. And if anyone do a cruelty in my name, then, though they say the name Aslan, it is Tash whom they serve and by Tash their deed is accepted.

But he himself that justifies also deifies, for by justifying he makes sons of God. “For he has given them power to become the sons of God.” If then we have been made sons of God, we have also been made gods.

God became man that man might become God.

[T]he Word became flesh and the Son of God became the Son of Man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God.

Do we cast blame on him [God] because we were not made gods from the beginning, but were at first created merely as men, and then later as gods? Although God has adopted this course out of his pure benevolence, that no one may charge him with discrimination or stinginess, he declares, “I have said, ye are gods; and all of you are sons of the Most High.” . . .

If the Word became a man, it was so men may become gods.

How, then, shall he become a God, who has not as yet been made a man? Or how can he be perfect who was but lately created? How, again, can he be immortal, who in his mortal nature did not obey his maker? For it must be that thou, at the outset, shouldest hold the rank of a man, and then afterwards partake of the glory of God.