St. Augustine:
“My judgment is true, says He, because I am not alone, but I and the Father that sent me.” Therefore, O Lord our God, Jesus Christ, Your sending is Your incarnation. So I see, so I understand: in short, so I believe, in case it may smack of arrogance to say, so I understand. Doubtless the Lord Jesus Christ is even here; rather, was here as to His flesh, is here now as to His Godhead: He was both with the Father and had not left the Father. Hence, in that He is said to have been sent and to have come to us, His incarnation is set forth to us, for the Father did not take flesh.
For there are certain heretics called Sabellians, who are also called Patripassians, who affirm that it was the Father Himself that had suffered. Do not thou so affirm, O Catholic; for if you will be a Patripassian, you will not be sane. Understand, then, that the incarnation of the Son is termed the sending of the Son; and do not believe that the Father was incarnate, but do not yet believe that He departed from the incarnate Son. The Son carried flesh, the Father was with the Son. If the Father was in heaven, the Son on earth, how was the Father with the Son? Because both Father and Son were everywhere: for God is not in such manner in heaven as not to be on earth.
Hear him who would flee from the judgment of God, and found not a way to flee by: “Whither shall I go,” says he, “from Your Spirit; and whither shall I flee from Your face? If I ascend up into heaven, You are there.” The question was about the earth; hear what follows: “If I descend unto hell, You are there.” If, then, He is said to be present even in hell, what in the universe remains where He is not present? For the voice of God with the prophet is, “I fill heaven and earth.” (Jeremiah 23:24) Hence He is everywhere, who is confined by no place. Turn not thou away from Him, and He is with you. If you would come to Him, be not slow to love; for it is not with feet but with affections you run. You come while remaining in one place, if you believe and lovest. Wherefore He is everywhere; and if everywhere, how not also with the Son? Is it so that He is not with the Son, while, if you believe, He is even with you?
How, then, is His judgment true, but because the Son is true? For this He said: “And if I judge, my judgment is true; because I am not alone, but I and the Father that sent me.” Just as if He had said, ‘My judgment is true, because I am the Son of God.’ How dost Thou prove that You are the Son of God? “Because I am not alone, but I and the Father that sent me.” Blush, Sabellian; you hear the Son, you hear the Father. Father is Father, Son is Son. He said not, ‘I am the Father,’ and ‘I the same am the Son’; but He says, “I am not alone.” Why are You not alone? Because the Father is with me. “I am, and the Father that sent me;” you hear, “I am, and He that sent me.” Lest thou lose sight of the person, distinguish the persons. Distinguish by understanding, do not separate by faithlessness; lest again, fleeing as it were Charybdis, thou rush upon Scylla. For the whirlpool of the impiety of the Sabellians was swallowing you, to say that the Father is the same who is Son: just now you have learned, “I am not alone, but I and the Father that sent me.” You acknowledge that the Father is Father, and that the Son is Son; you acknowledge rightly. But do not say the Father is greater, the Son is less; do not say, the Father is gold, the Son is silver. There is one substance, one Godhead, one co-eternity, perfect equality, no unlikeness. For if you only believe that Christ is another, not the same person that the Father is, but yet imagine that in respect of His nature He is somewhat different from the Father, you have indeed escaped Charybdis, but you have been wrecked on the rocks of Scylla.
Steer the middle course, avoid each of the two perilous sides. Father is Father, Son is Son. You say now, Father is Father, Son is Son: you have fortunately escaped the danger of the absorbing whirl; why would you go unto the other side to say, the Father is this, the Son that? The Son is another person than the Father is, this you say rightly; but that He is different in nature, you say not rightly. Certainly the Son is another person, because He is not the same who is Father and the Father is another person, because He is not the same who is Son: nevertheless, they are not different in nature, but the selfsame is both Father and Son. What means the self-same? God is one. You have heard, “Because I am not alone, but I and the Father that sent me:” hear how you may believe Father and Son; hear the Son Himself, “I and the Father are one.” (John 10:30) He said not, ‘I am the Father;’ or, ‘I and the Father is one person;’ but when He says, “I and the Father are one,” hear both, both the one, unum, and the are, sumus, and you shall be delivered both from Charybdis and from Scylla.
In these two words, in that He said one, He delivers you from Arius; in that He said are, He delivers you from Sabellius. If one, therefore not diverse; if are, therefore both Father and Son. For He would not say are of one person; but, on the other hand, He would not say one of diverse. Hence the reason why He says, “my judgment is true,” is, that you may hear it briefly, because I am the Son of God. But I would have you in such wise believe that I am the Son of God, that you may understand that the Father is with me: I am not Son in such manner as to have left Him; I am not in such manner here that I should not be with Him; nor is He in such manner there as not to be with me: I have taken to me the form of a servant, yet have I not lost the form of God; therefore He says, “I am not alone, but I and the Father that sent me.”
