In this, the final lecture of the Summer 2017 12-part series The Psychological Significance of the Biblical Stories, we encounter, first, Hagar’s banishment to the desert with Ishmael and then the demand made by God to Abraham for the sacrifice of Isaac. To sacrifice now is to gain later: perhaps the greatest of human discoveries. What, then, should best be sacrificed? And what might be the greatest gain? There are few eternal questions more profound and difficult.