"Take now your son ... and offer him ... as a burnt offering on one of the mountains of which I shall tell you" (Genesis 22:2)
A person's character determines how he interprets God's will (see Psalm 18:25-26).
Abraham interpreted God's command to mean that he had to kill his son, and he could only leave this traditional belief behind through the pain of a tremendous ordeal. God could purify his faith in no other way. If we obey what God says according to our sincere belief, God will break us from those traditional beliefs that misrepresent Him. There many such beliefs which must be removed - for example, that God removes a child because his mother loves him too much. That is the devil's lie and a travesty of the true nature of God! If the devil can hinder us from taking the supreme climb and getting rid of our wrong traditional beliefs about God, he will do so. But if we will stay true to God, God will take us through an ordeal that will serve to bring us into a better knowledge of Himself.
The great lesson to be learned from Abraham's faith in God is that he was prepared to do anything for God. He was there to obey God, no matter what contrary belief of his might be violated by his obedience. Abraham was not devoted to his own convictions or else he would have slain Isaac and said that the voice of the angel was actually the voice of the devil. That is the attitude of a fanatic. If yo will remain true to God, God will lead you directly through every barrier and right into the inner chamber of the knowledge of Himself. But you must always be willing to come to the point of giving up your own convictions and traditional beliefs. Don't ask God to test you. Never declare as Peter did that you are willing to do anything, even "to go ... both to prison and to death" (Luke 22:33). Abraham did not make any such statement - he simply remained true to God, and God purified his faith.