2 Corinthians / Question
Paul says God made them ministers of a new covenant, "not of the letter but of the Spirit." He states the contrast as: "the letter kills, but the Spirit gives life." See 2 Corinthians 3:6.
In 2 Corinthians 3:4–6, Paul explains the kind of confidence he has: it is not self-confidence, but confidence that comes “through Christ” and is directed “toward God.” He immediately denies that he and his coworkers are capable on their own to produce or credit anything as coming from themselves. These lines continue Paul’s defense and explanation of his ministry in the face of skepticism at Corinth.
Paul’s “confidence” is presented as real but not self-made. It is through Christ and aimed toward God (verse 4). He then blocks a misunderstanding: neither he nor his coworkers are “sufficient” in themselves to credit any meaningful ministry outcome to their own resources (verse 5). Any adequacy comes from God.
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with 2 Corinthians 3:6, then read the surrounding section so the answer stays connected to the passage's flow.
6who also made us sufficient as servants of a new covenant; not of the letter, but of the spirit. For the letter kills, but the spirit gives life.