For Abraham, Isaac was at the very center of both his own heart and of God’s promise. He loved Isaac very much as a father and Isaac was the fulfillment of God’s promises to him - a child of his old age - a miracle.
God was asking Abraham to trust Him with everything - his son and God’s promise.
The following two verses from Scripture make it clear that Abraham fully believed God would deliver Isaac back to him - even if it required resurrection.
Genesis 22:5 - He said to his servants, “Stay here with the donkey while I and the boy go over there. We will worship and then we will come back to you.”
Hebrews 11:17-19 - By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises was in the act of offering up his only son, 18 of whom it was said, “Through Isaac shall your offspring be named.” 19 He considered that God was able even to raise him from the dead, from which, figuratively speaking, he did receive him back.
God was not after Isaac. God wanted to strengthen Abraham’s faith. He was after Abraham’s heart. God never intended to let Abraham go through with this deed.
Moreover, this act prefigured Jesus. God did not require Abraham to offer his son - he provided a sacrifice in Isaac’s place just like God would one day offer up His own Son one day.
The story of Abraham and Isaac helps us remember both to trust God to keep His promises and to be in amazement of God’s love in giving His own Son.