As for those who say that the begotten is in its nature unlike the unbegotten, let them learn from the example of Adam and Abel not to talk nonsense. For Adam himself was not begotten according to the natural generation of men; but Abel was begotten of Adam. Now, surely, he who was never begotten is called unbegotten, and he who came into being by generation is called begotten; yet the fact that he was not begotten did not hinder Adam from being a man, nor did the generation of Abel make him at all different from man’s nature, but both the one and the other were men, although the one existed by being begotten, and the other without generation. So in the case of our statements as to the Divine nature, the fact of not being begotten, and that of being begotten, produce no diversity of nature, but, just as in the case of Adam and Abel the manhood is one, so is the Godhead one in the case of the Father and the Son.