Here "righteousness of the faith" means that God considered him to be righteous. AT: "a visible sign that God considered him righteous because he had believed in God before he was circumcised" (See: [[rc://en/ta/man/translate/figs-explicit]])
You can translate this in an active form. AT: "This means that God will consider them righteous" (See: [[rc://en/ta/man/translate/figs-activepassive]])
# 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. AT: "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]])