God Begat Isaac

"And the LORD remembered Sarah" (Genesis 21:1). Rabbi Yitzchak said: It is written, "And if the woman was not defiled but is pure, then she shall be cleared and shall conceive seed" (Numbers 5:28). This woman who entered the house of Pharaoh and the house of Abimelech and came out pure, is it not right that she should be remembered? Rabbi Yehudah son of Rabbi Simon said: Even though Rabbi Huna said there is an angel appointed over desire, yet Sarah did not need these things, but it was He in His own glory, "And the LORD remembered Sarah." "And Sarah conceived and bore Abraham a son in his old age" (Genesis 21:2). This teaches that she did not steal seed from another place. "A son in his old age" (li-zekunav) [read as if li-ziv ikonin, to the radiance of his features] teaches that the radiance of his features resembled his. "At the appointed time of which God had spoken to him" (Genesis 21:2). Rabbi Yudan and Rabbi Chama. Rabbi Yudan said: He was born at nine months, so that they would not say he was swept out of the house of Abimelech. Rabbi Chama said: At seven months, which are nine months curtailed. Rabbi Huna in the name of Rabbi Chizkiyah said: He was born at midday. "Appointed time" (moed) is said here, and "appointed time" is said elsewhere, "At the going down of the sun, the appointed time of your going out from Egypt" (Deuteronomy 16:6).