Irenaeus on Authentic Communion & John 3:18-21 Around 180CE

Communion with God is life and light, and the enjoyment of all the benefits which He has in store. But on as many as, according to their own choice, depart from God, He inflicts that separation from Himself which they have chosen of their own accord. But separation from God is death, and separation from light is darkness; and separation from God consists in the loss of all the benefits which He has in store. …

Now, good things are eternal and without end with God, and therefore the loss of these is also eternal and never-ending. It is in this matter just as occurs in the case of a flood of light: those who have blinded themselves, or have been blinded by others, are for ever deprived of the enjoyment of light. It is not, [however], that the light has inflicted upon them the penalty of blindness, but it is that the blindness itself has brought calamity upon them: and therefore the Lord declared, “He that believes in Me is not condemned,” that is, is not separated from God, for he is united to God through faith.

On the other hand, He says, “He that does not believe is condemned already, because he has not believed in the name of the only-begotten Son of God;” that is, he separated himself from God of his own accord. “For this is the judgment, that light is come into this world, and men have loved darkness rather than light. For every one who does evil hates the light, and does not come into the light, lest his deeds should be exposed. But he that does truth comes to the light, that his deeds may be made manifested as having been wrought in God.”

Irenaeus, Vol. 1, p. 935