Tertullian · a new plain-English translation from the original language
You will need to prove as plainly from the Scriptures as we prove that he made his Word his son. For if he names a son, and the son can be none other than the one who proceeded from him, and the Word is what proceeded from him, then it is the Word that will be the son, not the one from whom it proceeded: for its source of proceeding was not itself. You, however, who claim Father and Son are one and the same, thereby make that single person both the one issuing forth from himself and the one who has issued -- that is, God himself. He could have done that. But he did not. Or else produce a proof to match what I demand -- that is, show the Scriptures presenting the same person as both Son and Father in the very way we show Father and Son distinctly: distinctly, I say, not divided. As I quote God's own words, 'My heart has belched forth a most excellent word,' you in turn should set against me some place where God said, 'My heart has belched me forth as a most excellent word' -- so that he would be both the one who belched and the thing belched forth, both the one who put forth and the one put forth -- if indeed he is both the Word and God. Look, I set before you the Father saying to the Son, 'You are my son, today I have begotten you.' If you want me to believe that he is father and son at once, show me somewhere it is likewise said: 'The Lord said to himself, I am my own son, today I have begotten myself'; and again, 'Before the daystar I begot myself'; and, 'The Lord founded me as the first of his paths, meant for what he would accomplish; before every hill he brought me forth' -- or any other wording to that effect. Whom, after all, was the Lord God of the universe afraid of, that he should not have put it that way, if that is how things really stood? Or was he afraid he would not be believed, if he had simply declared himself to be both father and son? There was one thing, however, he did fear: that the author of truth should lie against himself and against his own truth. And so, believing God to be truthful, I know he pronounced nothing other than what he had ordained, and ordained nothing other than what he pronounced. You, on the other hand, would make him a liar, a deceiver, a betrayer of this very faith -- if, while he himself was his own son, he handed the role of son to someone else. Whereas all the Scriptures display both a demonstration and a distinction of the Trinity -- and it is from these that our own rule of argument is drawn -- that one and the same person cannot be seen to be the one who speaks, the one spoken of, and the one spoken to; since neither perversity nor deceit befits God, that, when he himself was the one being addressed, he should instead address another rather than himself. Take, then, further words of the Father concerning the Son, spoken through Isaiah: 'Here is my son, the one I have picked out, my dear one, in whom my soul delights; I shall lay my spirit upon him, and he will make judgment known to the nations.' And take also words addressed to him directly: 'It is too small a thing for you to be called my son, to restore the tribes of Jacob and turn back the dispersion of Israel; I have set you as a light to the nations, that you may be salvation to the ends of the earth.' Take now, too, the Son's own words concerning the Father: 'The Lord's spirit rests on me, since he has anointed me to bring good tidings to men.' Likewise in a psalm, addressed to the Father about that same anointing: 'Do not forsake me, until I proclaim your arm to the whole generation yet to come.' And in another: 'Lord, how they are multiplied who oppress me!' Indeed, almost all the psalms that carry the person of Christ present the Son speaking to the Father -- that is, Christ addressing God. Note too the Spirit speaking, in the third person, about the Father and the Son: 'The Lord said to my Lord, Sit at my right hand, until I make your enemies the footstool of your feet.' Likewise through Isaiah: 'Thus says the Lord to my Lord, the Christ.' And again through the same prophet, addressed to the Father about the Son: 'Lord, who has believed our report, and to whom has the arm of the Lord been revealed? We announced concerning him -- as it were a little child, as a root in thirsty ground; he had no form nor glory.' These are a few examples out of many: I have no ambition to unroll the whole of Scripture, since, even taking each passage as bearing witness to the full majesty and authority of the point, a larger engagement still awaits us further on. Even from these few, though, the distinction of the Trinity is plainly set out: since here is the Spirit in person doing the speaking, the Father as the one addressed, and the Son as the one described. So too with everything else that is pronounced -- now by the Father about the Son or to the Son, now by the Son about the Father or to the Father, now by the Spirit -- each instance establishes each person in his own proper character.