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 ...
Why is it so that if a Jew has a male child with a non-Jewish woman the child is not circumcised, even though, like Ishmail, the child is under Abrahamic (but not Mosaic) covenant, since the father is ...
Avraham Avinu was told to have a Bris at 99 years of age. Why didn't Hashem have him do a Bris earlier?