Q. Why did God want human sacrifices, for example, Isaac and Jesus?
Actually, the clear and consistent teaching of the Bible is that God does not want human sacrifices. I’ll demonstrate that in this post, and then in my next post I will consider the two cases you mention and explain why they are not exceptions.
The pagan nations surrounding ancient Israel did make human sacrifices to their gods, but the law of Moses insisted that this was not the way that Yahweh, the God of Israel, the Creator of the world, wanted to be worshipped. One law, in Leviticus, prohibits making any child a burnt offering to the Canaanite god Molech: “You are not to make any of your children pass through the fire to Molech. Do not profane the name of your God; I am Yahweh.” A more general law in Deuteronomy says, “Let no one be found among you who sacrifices their son or daughter in the fire.”
As I explain in this post, Jephthah, one of the judges, sacrificed his daughter in fulfillment of a vow because he was ignorant of the further law that said a human being who would otherwise be the subject of such a vow had to be “redeemed” (bought back), not sacrificed. This story is included in the book of Judges to show what tragic and evil things happen when “everyone does what is right in their own eyes.”
The other historical narratives in the Bible uphold this standard from the law of Moses and use it to evaluate the later Israelite kings. It is said about King Ahaz, for example, “He did not do what was right in the eyes of the Lord his God. He . . . even sacrificed his son in the fire, engaging in the detestable practices of the nations the Lord had driven out before the Israelites.” About King Manasseh it is said similarly, “He did evil in the eyes of the Lord, following the detestable practices of the nations the Lord had driven out before the Israelites. . . . He sacrificed his own son in the fire . . . He did much evil in the eyes of the Lord, arousing his anger.”
Such human sacrifices were a chief reason why the kingdom of Israel was taken into exile, again according to the historical biblical narratives: “All this took place because the Israelites had sinned against the Lord their God . . . They worshiped other gods and followed the practices of the nations the Lord had driven out before them . . . They sacrificed their sons and daughters in the fire. They . . . sold themselves to do evil in the eyes of the Lord, arousing his anger.”
The prophetic tradition within the Bible similarly says that God does not want human sacrifices. The prophet Micah, for example, reflecting on what he would have to offer to make up for his sins and be restored to God’s favor, considers greater and greater sacrifices, all the way up to the sacrifice of his own firstborn child, but then realizes that what God really wants is for him to live a life of humility and compassion:
With what shall I come before the Lord
and bow down before the exalted God?
Shall I come before him with burnt offerings,
with calves a year old?
Will the Lord be pleased with thousands of rams,
with ten thousand rivers of olive oil?
Shall I offer my firstborn for my transgression,
the fruit of my body for the sin of my soul?
He has shown you, O mortal, what is good.
And what does the Lord require of you?
To act justly and to love mercy
and to walk humbly with your God.
So the biblical teaching against human sacrifice is clear and consistent. Why, then, did God say to Abraham, “Take your son, your only son, whom you love—Isaac—and go to the region of Moriah. Sacrifice him there as a burnt offering on a mountain I will show you”? And why is the death of Jesus so often described as a “sacrifice”? I’ll explore both of these questions in my next post.
Good Question 
One thought on “Why did God want human sacrifices, for example, Isaac and Jesus?”