en_tn/php/03/03.md

For it is we who are

Paul uses "we" to refer to himself and all true believers in Christ, including the Philippian believers. (See: rc://en/ta/man/translate/figs-exclusive)

the circumcision

Paul uses this phrase to refer to believers in Christ who are not physically circumcised but are spiritually circumcised, which means they have received the Holy Spirit through faith. Alternate translation: "the truly circumcised ones" or "truly God's people"

have no confidence in the flesh

Here "flesh" is a metonym for anything concerning one's body, such as his ancestry, whether or not he has been circumcised, and what he does. To have no confidence in the flesh means to understand that those things cannot make a person right with God. Alternate translation: "do not trust in anything about ourselves to make us right with God" (See: rc://en/ta/man/translate/figs-metonymy)