God commanded Abraham to sacrifice his adult son, Isaac, as a type of what God would do to Jesus
We saw above how God promised to form a nation (Israel) through Abraham. God told him that that promise would be fulfilled through his adult son Isaac and through no other son. However, when Isaac was about 33 years of age God told Abraham to go to Mount Moriah (known to us now as Mount Calvary) and to kill his son Isaac and offer him to God as a sacrifice. Abraham went to Mount Moriah (Calvary) with a heavy heart, dreading what he had to do. But he was willing to do it because God had commanded him to do so.
God allowed this test to go on until almost the last minute. Isaac was placed on an altar. He fully cooperated, even though he was a grown man and could have resisted Abraham. However, at the last moment God told Abraham not to do it. It had been a test of Abraham's faith and obedience and he (and Isaac) had passed that test. Abraham went into that test fully believing that if Isaac was killed on the altar as a sacrifice then God would, inevitably, raise him from the dead. He knew that because God had promised that His chosen nation (Israel) would come through Isaac. Thus he believed that resurrection would be the way for that promise to be fulfilled, i.e. that God would raise Isaac from the dead.
In the end, however, God did not make Abraham go through with it. He stopped him. I will set out the account of this from Genesis 22 because it is a very important drama. It perfectly acts out for us what God the Father was willing to go through 2000 years later when He sacrificed His own Son, Jesus:
1Now it came about after these things, that God tested Abraham, and said to him, "Abraham!" And he said, "Here I am." 2He said, "Take now your son, your only son, whom you love, Isaac, and go to the land of Moriah, and offer him there as a burnt offering on one of the mountains of which I will tell you." 3So Abraham rose early in the morning and saddled his donkey, and took two of his young men with him and Isaac his son; and he split wood for the burnt offering, and arose and went to the place of which God had told him. Genesis 22:1-3 (NASB)
9Then they came to the place of which God had told him; and Abraham built the altar there and arranged the wood, and bound his son Isaac and laid him on the altar, on top of the wood. 10Abraham stretched out his hand and took the knife to slay his son. 11But the angel of the LORD called to him from heaven and said, "Abraham, Abraham!" And he said, "Here I am." 12He said, "Do not stretch out your hand against the lad, and do nothing to him; for now I know that you fear God, since you have not withheld your son, your only son, from Me." 13Then Abraham raised his eyes and looked, and behold, behind him a ram caught in the thicket by his horns; and Abraham went and took the ram and offered him up for a burnt offering in the place of his son. 14Abraham called the name of that place The LORD Will Provide, as it is said to this day, "In the mount of the LORD it will be provided." Genesis 22:9-14 (NASB)
Not only did God do the very same thing with His Son, Jesus. He actually did it in the very same place, i.e. Mount Calvary, which is also called Mount Moriah. What is more, Isaac and Jesus were about the same age, 33. Although in our traditions Isaac is portrayed as a boy, he was in fact a man. That is how he is portrayed in Jewish circles. In their children's books, when the account of Abraham and Isaac is told, Isaac is correctly pictured as a fully grown man.
The main reason God put Abraham through that ordeal was to test his faith. It was also to provide us with a vivid and dramatic illustration of what Jesus our Messiah and Saviour would one day do for us. See how much emphasis is placed in both the Old Testament and in the New Testament, especially in the letter to the Hebrews, on the shedding of blood. God is making clear that only the shedding of Jesus’ blood, i.e. His death in our place, could pay the price for our sins and enable us to be forgiven. (See chapter 10 for more detail on the importance of the blood of Jesus being shed for us).
Another reason why God had to go to such enormous trouble to establish the nation of Israel as His chosen nation, was that there had to be a place where it would be possible for Jesus, the Messiah, to be born and brought up without sinning. In any other nation, if Jesus had obeyed his parents, He would have had to engage in idolatry and worship false gods. Yet, to disobey His parents would have been sin in itself. So there had to be a nation which worshiped the one true God. Then Jesus could obey His parents without dishonouring God. This was vital, because Jesus had to live a perfectly sinless life.