When Abraham was told by God to circumcise HIMSELF ... he did it immediately! When Abraham was told to offer his son Isaac, he had to walk 3 days with teenage Isaac to Mt Moriah.
3 days to think long and very hard about what he was asked to do by his God - and not a single lick of it made any sense. Abraham waited 25 years for Issac to be born, and now his Isaac was the ONLY direct path to the other promises!
I'm certain Abraham had little idea of what was fully to happen, but it's clear in Gen 22:5 that he knew that somehow they'd both be back:
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.”
In the end, God's grace provided a ram and Abraham walked back from Mt Moriah sure of who he was in His Father and 100% fully confident in the goodness of His God.
Understanding the directives of God will never be a pre requisite for our obedience, and obedience will always be BETTER than sacrifice.
Genesis 22:1-19; 1 Samuel 15:22