Tertullian

“ I can never myself be my own wife. In like manner, in order to be a father, I have a son, for I never can be a son to myself; and in order to be a son, I have a father, it being impossible for me ever to be my own father. ”

“ Now a Father makes a Son, and a Son makes a Father; [2] and they who thus become reciprocally related out of each other to each other cannot in any way by themselves simply become so related to themselves, that the Father can make Himself a Son to Himself, and the Son render Himself a Father to Himself. And the relations which God establishes, them does He also guard. A father must needs have a son, in order to be a father; so likewise a son, to be a son, must have a father. ”

“ For it was necessary that there should be both kites and heretics; it was necessary also that the Father should be crucified. [7] In one sense there will be something difficult even for God—namely, that which He has not done—not because He could not, but because He would not, do it. For with God, to be willing is to be able, and to be unwilling is to be unable; all that He has willed, however, He has both been able to accomplish, and has displayed His ability. Since, therefore, if God had wished to make Himself a Son to Himself, He had it in His power to do so ”