25. There remains, I conceive, no possibility of doubt but that the words, I and the Father are One, were spoken with regard to the nature which is His by birth. The Jews had rebuked Him because by these words He, being a man, made Himself God. The course of His answer proves that, in this I and the Father are One, He did profess Himself the Son of God, first in name, then in nature, and lastly by birth. For I and Father are the names of substantive Beings; One is a declaration of Their nature, namely, that it is essentially the same in Both; are forbids us to confound Them together; are one, while forbidding confusion, teaches that the unity of the Two is the result of a birth. Now all this truth is drawn out from that name, the Son of God, which He being sanctified by the Father, bestows upon Himself; a name, His right to which is confirmed by His assertion, I and the Father are One. For birth cannot confer any nature upon the offspring other than that of the parent from whom that offspring is born.