Abraham was extraordinary. For the longest time I could not figure out how he could offer his son as a sacrifice. Then once I understood how blood covenants work, and how clearly he saw the coming messiah, I could see.
Abraham your father rejoiced that he would see my day, and he saw it and was glad.” John 8:56
If I may, the reason that Abraham could sacrifice his son, though I'm sure that it was still difficult, was because God had previously said that the promise made to Abraham would come through his son Isaac and therefore as Paul said regarding this:
"By faith Abraham, when God tested him, offered Isaac as a sacrifice. He who had embraced the promises was about to sacrifice his one and only son, even though God had said to him, “It is through Isaac that your offspring will be reckoned.” Abraham reasoned that God could even raise the dead, and so in a manner of speaking he did receive Isaac back from death."
Therefore, Abraham knew that if he sacrificed his son that God would have to resurrect him in order to keep his promise when God said "It is through Isaac that your offspring will be reckoned."