45. The above opinion, although meant to teach the immutability of God, yet prepared the way for the following heresy. Some have ventured to say that the Unborn God by expansion of His substance extended Himself as far as the holy Virgin, in order that this extension produced by the increase of His nature and assuming manhood might be called Son. They denied that the Son who is perfect God born before time began was the same as He who was afterwards born as Man. Therefore the Catholic Faith condemns all denial of the immutability of the Father and of the birth of the Son.