Chazal tells us (Midrash Rabbah Bereishis 64:4 and 95:3; Yoma 28b, based on. Gen. 26:5; Kiddushin 82a) that the Patriarchs observed the mitzvahs before they were given. But Avraham did not circumcize ...
The Midrash says (Bereshis Rabbah 49:13 quoted in Rashi Genesis 18:32) that Abraham stopped asking HaShem to save Sodom in the merit of less than 10 people because Noah and his family who were 8 ...
One of the difficult tests Avraham Avinu faced was when Nimrod threw him into the (Kivshan Haish) fire. It is not mentioned in the Torah at all. Why?