Hilary of Poitiers On the Christian God Visiting Abraham as איש

God speaks to Abraham and there assures him that Sara shall give birth. Later, while he is seated, three men appear before him. He adores one and confesses that He is the Lord, and this same one whom he adores and confesses assures him that He will return at the same time, and as God told Abraham that Sara would have a son. The same man, whom he saw later on, speaks to the same one about these very subjects. Only the name has been changed, but nothing has been missing from the confession. Although Abraham saw Him as a man, he adored Him as the Lord, that is, he recognized the mystery of the future Incarnation. Nor do we lack a testimonial to such great faith, for the Lord declares in the Gospels: 'Abraham your father rejoiced that he was to see my day. He saw it and was glad.' The man who was seen, therefore, promises that He will return at the same time. Watch for the outcome of this promise, but remember that it is a man who makes this promise! What, therefore, does Scripture say: 'And the Lord visited Sara.' Hence, that man is the Lord who fulfills what He has promised. Then what follows? And God did to Sara as he said.' He is called a man when He is speaking, He is designated as the Lord when He is visiting, and He is proclaimed as God by His action. Certainly you are aware that it was a man who was seen by Abraham and conversed with him. How will you not recognize Him as God, since the same Scripture, which had stated that He was a man, also acknowledged Him as God? For, it has said: 'And Sara conceived and bore Abraham a son in his old age, and at the time as the Lord had said to him.'60 But the man declared that He would come. Consider Him only as a man unless He who comes is also the Lord and God. [Hilary of Poitiers, On the Trinity 4.27]