Firstborn among brothers; God is his own Father

From Luke. “And it came to pass while they were there that the days were fulfilled for her to give birth, and she bore her son, the firstborn, and wrapped him and laid him in the manger, because there was no place for them in the lodging.” The holy virgin has borne one and only son, Emmanuel. How then does it say “her son, the firstborn”? For others have not come to be after him, and she has remained a virgin. So it is marked from the God-breathed scripture: the Only-begotten Word of God has been named firstborn. For he has shared blood and flesh and similarly to us shared the same things. Thus he became firstborn among many brothers; yet as God he is worshiped by us ourselves and by the spirits above.

“And his mother said to him: Child, why have you done thus to us? See, your father and I, being in pain, were seeking you. And he said to them: Why is it that you were seeking me? Did you not know that I must be in the things of my Father?” Observe how he names as his own Father the one in the heavens. But if he were a human alone, and understood as that very thing according to us, how would it not rather have been necessary to say: Did you not know that I must be in the things of the Father of all? But he makes him his own. For he alone has been begotten from him by nature divinely; and the same one, having also become human, has God as Father by nature and as his own.