28. I call to mind that, at the beginning of our treatise Book i. § 19, iv. § 2, vi. § 9., I gave the warning that human analogies correspond imperfectly to their Divine counterparts, yet that our understanding receives a real, if incomplete, enlightenment by comparing the latter with visible types. And now I appeal to human experience in the matter of birth, whether the source of their children’s being remain not within the parents. For though the lifeless and ignoble matter, which sets in motion the beginnings of life, pass from one parent into the other, yet these retain their respective natural forces. They have brought into existence a nature one with their own, and therefore the begetter is bound up with the existence of the begotten; and the begotten, receiving birth through a force transmitted, yet not lost, by the begetter, abides in that begetter. This may suffice as a statement of what happens in a human birth. It is inadequate as a parallel to the perfect birth of God the Only-begotten; for humanity is born in weakness and from the union of two unlike natures, and maintained in life by a combination of lifeless substances. Again, humanity does not enter at once into the exercise of its appointed life, and never fully lives that life, being always encumbered with a multitude of members which decay and are insensibly discarded. In God, on the other hand, the Divine life is lived in the fullest sense, for God is Life; and from Life nothing that is not truly living can be born. And His birth is not by way of emanation but results from an act of power. Thus, since God’s life is perfect in its intensity, and since that which is born from Him is perfect in power, God has the power of giving birth but not of suffering change. His nature is capable of increase Cf. the next section., not of diminution, for He continues in, and shares the life of, that Son to Whom He gave in birth a nature like to, and inseparable from, His own. And that Son, the Living born from the Living, is not separated by the event of His birth from the nature that begat Him.