Genesis
22:2 And he said, Take now thy son, thine only [son] Isaac, whom thou
lovest, and get thee into the land of Moriah; and offer him there for a burnt
offering upon one of the mountains which I will tell thee of.
22:3 And Abraham rose up early in the morning, and saddled his ass, and took two
of his young men with him, and Isaac his son, and clave the wood for the burnt
offering, and rose up, and went unto the place of which God had told him.
22:4 Then on the third day Abraham lifted up his eyes, and saw the place afar
off.
22:5 And Abraham said unto his young men, Abide ye here with the ass; and I and
the lad will go yonder and worship, and come again to you.
22:6 And Abraham took the wood of the burnt offering, and laid [it] upon Isaac
his son; and he took the fire in his hand, and a knife; and they went both of
them together.
22:7 And Isaac spake unto Abraham his father, and said, My father: and he said,
Here [am] I, my son. And he said, Behold the fire and the wood: but
where [is] the lamb for a burnt offering?
22:8 And Abraham said, My son, God will provide himself a
lamb for a burnt offering: so they went both of them together.
22:9 And they came to the place which God had told him of; and Abraham built an
altar there, and laid the wood in order, and bound Isaac his son, and laid him
on the altar upon the wood.
22:10 And Abraham stretched forth his hand, and took the knife to slay his son.
22:11 And the angel of the LORD called unto him out of heaven, and said,
Abraham, Abraham: and he said, Here [am] I.
22:12 And he said, Lay not thine hand upon the lad, neither do thou any thing
unto him: for now I know that thou fearest God, seeing thou hast not withheld
thy son, thine only [son] from me.
22:13 And Abraham lifted up his eyes, and looked, and behold behind [him] a ram
caught in a thicket by his horns: and Abraham went and
took the ram, and offered him up for a burnt offering in the stead of his son.
(In addition to Abraham being willing to offer up Isaac to the Lord, it is also seen in verse 7 above, that Isaac had been with his father during other sacrifices to the Lord and knew that a "lamb" was missing.)