And it was at that time that Avraham traveled from Elonei Mamre and went to the land of the Philistines and sojourned in Gerar. Twenty-five years after Avraham's dwelling in the land of Canaan, which is one hundred years of Avraham's life [(this is Year 2048)], Avraham came to the land of the Philistines, to Gerar, etc. And Avimelech sent and took Sarah, etc. And it was toward evening that he sat on the throne and fell asleep, and behold an angel of HaShem came with his sword drawn and sought to kill him for the woman, etc.

And on that night all the inhabitants of the land saw the form of a man with a sword and he struck all the inhabitants of the land [(Sefer HaYashar, chapter 21). Avimelech's rectification was through Avimelech son of Yeruba'al (see Year 2916)].

And it was at that time, at the end of days and four months of Avraham's dwelling in the land of the Philistines in Gerar, that Sarah conceived and bore a son and called his name Yitzchak. He was born in Year 2048 [(and in Sefer Beit Yisrael it says Year 2048 is a typographical error)], when Avraham was one hundred, Sarah was ninety, and Yishmael was fourteen, and he lived one hundred and eighty years.

He was born after nine months, but some say after seven months which are nine incomplete months [(Bereishit Rabbah chapter 52)]. On the fifteenth of Nisan Yitzchak was born. [And in Tanchuma, Parashat Pekudei, it says on the second of Nisan Yitzchak was born.] At midday Yitzchak was born [(Bereishit Rabbah there). And the Rashla'l on Vayera writes that the angel said "at this appointed time" and announced "when the day is warm" which is the sixth hour, etc.

The text continues with extensive calculations about whether the year was a leap year, the timing of the birth, and the spiritual aspects of Yitzchak's creation, including that Chavah was reincarnated in Yitzchak, and that Yitzchak's soul spark was from Gavriel, and he was later reincarnated in Pinchas.]