The Start of The Great Lent

And Abraham took the wood of the burnt offering 

and laid it on Isaac his son. 

And he took in his hand the fire and the knife. 

So they went both of them together. 

Genesis 22:6

After these things God tested Abraham and said to him, “Abraham!” And he said, “Here I am.”
        

He said, “Take your son, your only son Isaac, whom you love, and go to the land of Moriah, and offer him there as a burnt offering on one of the mountains of which I shall tell you.”
        

So Abraham rose early in the morning, saddled his donkey, and took two of his young men with him, and his son Isaac. And he cut the wood for the burnt offering and arose and went to the place of which God had told him.
        

On the third day Abraham lifted up his eyes and saw the place from afar.
        

Then Abraham said to his young men, “Stay here with the donkey; I and the boy will go over there and worship and come again to you.”
        

And Abraham took the wood of the burnt offering and laid it on Isaac his son. And he took in his hand the fire and the knife. So they went both of them together.
        

And Isaac said to his father Abraham, “My father!” And he said, “Here I am, my son.” He said, “Behold, the fire and the wood, but where is the lamb for a burnt offering?”
        

Abraham said, “God will provide for himself the lamb for a burnt offering, my son.” So they went both of them together.
       
Genesis 22: 1-8

            
        

That Isaac Carries on himself "the wood for the burnt offering" is a figure, because Christ also "himself carried His own cross," and yet to carry "the wood for the burnt Offering" is the duty of a priest.
        

He therefore becomes victim and priest. But what is added also is related to this: "And they both went off together." For when Abraham carries the fire and knife as if to sacrifice, Isaac does not go behind him but with him that he might be shown to contribute equally with the priesthood itself.
       
 Origen