17. But meanwhile let us see what ground these men have for the confidence with which they forbid us to accept as true the utterances of God concerning Himself; utterances, the authenticity of which they do not deny. What more grievous insult could be flung by human folly and insolence at God’s self-revelation, than a condemnation of it, shewn in correction? For not even doubt and criticism will satisfy them. What more grievous than this profane handling and disputing of the nature and power of God? Than the presumption of saying that, if the Son is from God, then God is changeable and corporeal, since He has extended or developed a part of Himself to be His Son? Whence this anxiety to prove the immutability of God? We confess the birth, we proclaim the Only-begotten, for so God has taught us. You, in order to banish the birth and the Only-begotten from the faith of the Church, confront us with an unchangeable God, incapable, by His nature, of extension or development. I could bring forward instances of birth, even in natures belonging to this world, which would refute this wretched delusion that every birth must be an extension. And I could save you from the error that a being can come into existence only at the cost of loss to that which begets it, for there are many examples of life transmitted, without bodily intercourse, from one living creature to another. But it would be impious to deal in evidences, when God has spoken; and the utmost excess of madness to deny His authority to give us a faith, when our worship is a confession that He alone can give us life. For if life comes through Him alone, must not He be the Author of the faith which is the condition of that life? And if we hold Him an untrustworthy witness concerning Himself, how can we be sure of the life which is His gift?