Origen's homilies on Genesis
Abraham took the wood for the burnt offering, loaded it on Isaac, and carried in his own hands the fire and the knife. Then the two of them set out together. Isaac himself carries the wood for his own holocaust: this is a figure of Christ. For Christ carried the burden of the cross himself, and yet to carry the wood for the holocaust is really the duty of the priest. So Christ is then both victim and priest. This is the meaning of the expression: they set out together. For when Abraham, who was to perform the sacrifice, carried the fire and the knife, Isaac did not walk behind him, but with him. In this way he showed that he exercised the priesthood equally with Abraham.
What happened next? Isaac spoke to his father Abraham, ‘Father’ he said. This plea from the son was at that instant the voice of temptation. For do you not think the voice of the son who was about to be sacrificed struck a responsive chord in the heart of the father? Although Abraham did not waver because of his faith, he responded with a voice full of affection: ‘Yes, my son’ he replied. ‘Look,’ said Isaac, ‘here are the fire and the wood, but where is the lamb for the burnt offering?’ Abraham answered, ‘My son, God himself will provide the lamb for the burnt offering’.
The careful yet loving response of Abraham moves me greatly. I do not know what he saw in spirit, because he did not speak of the present but of the future: God himself will provide the lamb. His son asks what is to happen now, but Abraham’s reply concerns the future. Indeed the Lord himself provided a lamb, in Christ.
Abraham stretched out his hand and seized the knife to kill his son. But the angel of the Lord called to him from heaven. ‘Abraham, Abraham’ he said. ‘I am here’ Abraham replied. ‘Do not raise your hand against the boy’ the angel said. ‘Do not harm him, for now I know you fear God’. Compare this to what St Paul says when he speaks of God: He did not spare his own Son but gave him up for us all. God emulates man with magnificent generosity. Abraham offered to God his mortal son who did not die; God gave up his immortal Son who died for all of us.
Then looking up, Abraham saw a ram caught by its horns in a bush. We said before that Isaac is a type of Christ. Yet this also seems true of the ram. It is worth understanding how both are figures of Christ – Isaac who was not killed and the ram which was. Christ is the Word of God, but the Word became flesh.
Christ therefore suffered, but in the flesh. Christ, the bodily Christ, endured death; and the ram signifies that body and that death. As John said: Behold the lamb of God, behold him who takes away the sins of the world. The Word, on the other hand, remained incorruptible. This is Christ according to the spirit, and Isaac signifies that spirit. Therefore, Christ himself is both victim and priest according to the spirit. For he offers the victim to the Father according to the flesh, and he is himself offered on the altar of the cross.