"And he gave to him bris milah. And thus Avraham Avinu became the father of Yitzchak and he did his bris milah on the Yom HaShemini and Yitzchak became the father of Ya'akov and Ya'akov of the Sheneym Asar HaAvot. [BERESHIS 17:9-14; 21:2-4; 25:26; 29:31-35; 30:5-13, 17-24; 35:16-26]