From his book God in Search of Man:
Man had to be expelled from the Garden of Eden; he had to witness the murder of half of the human species by Cain out of envy; experience the catastrophe of the Flood; the confusion of the languages; slavery in Egypt and the wonder of the Exodus, to be ready to accept the law.
Continue reading More Abraham Joshua Heschel: on the Law, God’s Timing and Man’s Readiness