Not much longer could the terrible truth be hidden from Isaac. With what feelings must he have seen the agonised face of his father as he turned to bind him and as he learned that he must prepare not to sacrifice but to be sacrificed. Here then was the end of those great hopes on which his youth had been fed. What could such contradiction mean? Was he to submit even to his father in such a matter? Why should he not expostulate, resist, flee? Such ideas seem to have found short entertainment in the mind of Isaac. Trained by long experience to trust his father, he obeys without complaint or murmur. Still it cannot cease to be matter of admiration and astonishment that a young man should have been able on so brief a notice, through so shocking a way, and with so startling a reversal of his expectations, to forego all right to choose for himself, and yield himself implicitly to what he believed to be God's will. By a faith so absolute Isaac became indeed the heir of Abraham. When he laid himself on the altar, trusting his father and his God, he came of age as the true seed of Abraham and entered on the inheritance, making God his God. At that supreme moment he made himself over to God, he put himself at God's disposal; if his death was to be helpful in fulfilling God's purpose he was willing to die. It was God's will that must be done, not his. He knew that God could not err, could not harm His people; he was ignorant of the design which his death could fulfil, but he felt sure that his sacrifice was not asked in vain. He had familiarised himself with the thought that he belonged to God; that he was on earth for God's purposes not for his own; so that now when he was suddenly summoned to lay himself formally and finally on God's altar, he did not hesitate to do so. He had learned that there are possessions more worth preserving than life itself, that "Manhood is the one immortal thing Beneath Time's changeful sky"-- he had learned that "length of days is knowing when to die."