en_tn_lite_do_not_use/2co/03/05.md

competent in ourselves

"qualified in ourselves" or "sufficient in ourselves"

to claim anything as coming from us

Here the word "anything" refers to anything pertaining to Paul's apostolic ministry. Alternate translation: "to claim that anything we have done in ministry comes from our own efforts" (See: rc://en/ta/man/jit/figs-explicit)

our competence is from God

"God gives us our sufficiency"