Genesis 22:10-12

Then he reached out his hand and took the knife to slay his son. But the angel of the LORD called out to him from heaven, ‘Abraham! Abraham!’ ‘Here I am,’ he replied. ‘Do not lay a hand on the boy,’ he said. ‘Do not do anything to him. Now I know that you fear God, because you have not withheld from me your son, your only son.’