What does Genesis 22:12 mean?In complete and unhesitating obedience to God, Abraham was preparing to kill Isaac as he lay tied up on an altar. Knife in hand, Abraham is stopped by an urgent voice from heaven calling out his name. Now the angel of the Lord makes it clear: Don't hurt the boy in any way. This was God's plan all along, and Abraham has passed God's test of his faith.
The angel of the Lord, truly the Lord in another form, goes on: Now I know that you fear God since you have not withheld your only son from me. In the Old Testament, especially, to "fear God" means to have such great respect and reverence for the Lord's power and righteousness that you obey Him above all others. God's test satisfied the question of whether Abraham "feared" God once and for all.
Abraham's faith, we should note, is not ignorant or blind. Instead, he is choosing to trust God as a result of prior experiences. Time and again, God has proven that Abraham does not need to understand every detail, he merely needs to obey. God will work to prove His own righteousness in the end. Here, again, this is proven to be the case, though in a far more direct and dramatic form.
The Lord again refers to Isaac as "your son, your only son." We must not miss the parallel to John 3:16: "For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life."