Here "the circumcision" is a metonym that refers to the Jews. You can translate this in an active form. Alternate translation: "Jesus Christ has become a servant of the Jews" (See: [[rc://en/ta/man/jit/figs-metonymy]] and [[rc://en/ta/man/jit/figs-activepassive]])
Here "the fathers" refers to the ancestors of the Jewish people. You can translate this in active form. Alternate translation: "the promises that God gave to the ancestors of the Jews" (See: [[rc://en/ta/man/jit/figs-explicit]] and [[rc://en/ta/man/jit/figs-activepassive]])