RobH_en_tn/rom/04/12.md

Abraham became the father of the circumcision

Here "the circumcision" refers to those who are true believers in God, both Jews and Gentiles.

who follow in the steps of faith of our father Abraham

Here "follow in the steps of faith" is an idiom that means to follow someone's example of follow. Alternate translation: "who follow our father Abraham's example of faith" or "who have faith as our father Abraham did" (See: rc://en/ta/man/translate/figs-idiom)