Paul writes that he is honest in his ministry by preaching Christ, not praising himself. He shows the death and the life of Jesus in how he lives so that life can work in the Corinthian believers.
This phrase explains how Paul and his coworkers "have this ministry." It is a gift that God has given to them through his mercy. Alternate translation: "because God has shown us mercy" (See: [[rc://en/ta/man/translate/figs-explicit]])