Rabbi Jannai said: The Egyptians did not enslave the Israelites but for one hour of the day of the Holy One, blessed be He, (that is to say, for) 83⅓ years. Whilst yet Moses was not born, the magicians said to Pharaoh: In the future a child will be born, and he will take Israel out of Egypt. Pharaoh thought, and said: Cast ye all the male children into the river, and he will be thrown in with them, and thereby the word (of the magicians) will be frustrated; therefore they cast all the (male) children into the river.