“Pharaoh commanded all his people, saying: Every son that is born, you shall cast him into the Nile, and every daughter you shall keep alive” (Exodus 1:22). “Pharaoh commanded all his people,” Rabbi Yosei ben Rabbi Ḥanina says: He issued the decree even against his own people. Why did he do so? It is because his astrologers said to him: ‘The redeemer of Israel has already been conceived by his mother, but we do not know whether he is Israelite or Egyptian.’
At that moment, Pharaoh gathered all the Egyptians and said to them: ‘Lend me your sons that will be born for [the next] nine months so I will cast them into the Nile.’45The belief was that the Nile River was a deity and would repay those who worshipped it. That is what is written: “Every son that is born, [you shall cast him] into the Nile.” “Every Israelite son” is not written but rather, “every son,” whether Israelite or Egyptian.
But they [the Egyptians] did not want to accept it from him, as they said: ‘An Egyptian son will never redeem them, but rather, one from the Hebrew women.’ “Cast him into the Nile.” Why did they decree to cast them into the Nile? It is because the astrologers foresaw that the redeemer of Israel would be condemned by means of water, and they believed that he would drown in water.
But it was, in fact, only by means of a well that the decree of death was issued against him, as it is stated: “Because you did not have faith in me…[therefore you shall not bring this assembly into the land that I have given them; these are the waters of dispute…]” (Numbers 20:12–13). The Rabbis say that they [the astrologers] devised [this] counsel so that the Holy One blessed be He would not take vengeance against them by means of water.
Because they knew that the punishments of the Holy One blessed be He fit the crime, and they were certain that He would not bring a flood to the world; therefore, they commanded to drown them in water. “And every daughter you shall keep alive.” Why did Pharaoh need to keep the females alive? Rather, this is what they would say: ‘We will kill the males and take the females as wives,’ because the Egyptians were engulfed with lewdness.