Anonymous wrote:Circumcision in Judaism can't be boiled down to a "rule." It's a sign of God's covenant with Jews.
Right. It's a way to mark and distinguish Jewish men from other men. Now you could ask why God didn't just do that himself, or make everyone Jewish, I guess, but those are different questions. In the Torah it says that when Abraham accepted the covenant with God, he circumcised himself and his son (and possibly servants, I can't recall) as a sign. He had a choice. Presumably the gentiles he lived among either didn't get that choice, or didn't make it for themselves. Hence the difference and the need for a distinguishing mark.
Also, the Torah is full of stories of testing people with physical hardships. Circumcision is one.