en_tn/rom/04/12.md

He is also the father of the circumcised

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

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 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)