God allowed Isaac to live out of mercy for Abraham, not out of moral right. God cannot command evil.
The story of Abraham and Isaac can only be understood in the context of God’s relationship to Abraham. It cannot be extracted and applied to the present situation precisely because it is a pivotal and unique event in salvation history.
Recall that God promised Abram that he would be the father of a nation who would number as many as the stars (hidden from Abraham but visible to God in the daylight sun).
Did Abraham trust God? In some sense he did, however…
After this promise Abraham did have a son, Ishmael, through Sarai’s Egyptian maid Hagar.
When God let Abraham know that the son who would fulfill his promise to Abraham was not Ishmael but a son to be born through his post-menopausal wife, Sarah, Abraham laughed. And so did Sarah. (The name Isaac means “laughter.”)
After Isaac was born, Abraham, acting on his own, sent Hagar and Ishmael into the desert of Bersheeba with little in the way of food or water in order that they would both die. This was a death sentence that Abraham pronounced on Hagar and Ishmael. Unknown to Abraham, God intervened and saved them both.
Why did God test Abraham by asking him to sacrifice Isaac?
Precisely because Abraham did not trust God. He tried to make things that God promised happen in his own way. God was asking Abraham to trust in God’s plan and not take it over.
Abraham thought his first son Ishmael was dead so when God emphasized, “Your only son, Isaac…” that stung Abraham’s conscience because he realized that his actions had completely forsaken God’s covenant with him. He had proven himself untrustworthy and unworthy of a covenant with God because he was responsible (he thought) for the killing of Hagar and Ishmael. In Abraham’s mind, God was taking Isaac away from him because God’s promise of making him the father of a nation had been justly revoked by God.
God demanding that Abraham sacrifice Isaac was to drive the point home to Abraham that God was in charge and that he had jeopardized that. The promise that he would be the father of a nation was being revoked. The fact that Abraham completely understood this was demonstrated by his willingness to leave Isaac in the hands of God. By giving him over to God, so to speak, he was letting God determine the outcome. Abraham was no longer worthy of God’s promise, so it was being taken away from him through the sacrifice of Isaac. Recall that sacrifice in the Old Testament was done in atonement for wrongs done, in this case for the “killing of Hagar and Ishmael.”
Only through Abraham turning Isaac back over to God was the promise fulfilled. Abraham had shown trust in God, but also had an overpowering realization of his own failings.
This says nothing in terms of the justification of sacrificing children. If anything, it is confirmation that God does not want the sacrifice of children, as was prevalent in the area at the time and later. Furthermore,
what this episode demonstrates is quite contrary to what you think it shows. It actually came about show that Abraham did not do the right thing by abandoning Hagar and Ishmael to die in the wilderness. Which is precisely the justification of pro choice advocates: abandon preborn children to death if they are not ”in your plan."
The observations of KP3243 in post #19 are right on in terms of showing the detailed way in which God used the episode to foreshadow God’s fulfillment of the promise to Abraham and Abraham’s prophecy that, “God himself will (future tense) provide the lamb.”