en_tn/rom/04/12.md

General Information:

Paul is saying that circumcision alone does not make a man a descendant of Abraham, that is, a true Jew. A true Jew is one who has been circumcised and who lives by faith the way Abraham did.

He is also the father of the circumcised

Here "the circumcision" refers to Jews.

who also walk in the footsteps of the faith that our father Abraham had

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