en_tn/gal/05/03.md

I testify

"I declare" or "I serve as a witness"

to every man who lets himself be circumcised

Paul is using circumcision as a metonym for being Jewish. AT: "to every person who has become a Jew" (See: rc://en/ta/man/translate/figs-metonymy)

he is obligated to obey

"he must obey"