17 By faith Abraham, when he was tested, offered up Isaac on the altar. He who had received the promises was ready to offer his one and only son,11:17 Or only begotten son or unique son 18 even though God had said to him, "Through Isaac your offspring will be reckoned."11:18 Genesis 21:12 19 Abraham reasoned that God could raise the dead, and in a sense, he did receive Isaac back from death.