What does 2 Corinthians 3:6 mean?
Paul is writing about confidence in his own ministry. He has been clear, though, that this is not the same as confidence in himself. He and his co-workers are not claiming that anything of value comes from them. His authority as an apostle is not based on his skill and knowledge and aptitude. It is based only on God's authority and power to act through him.Paul now writes that God is the one who has made him and the other apostles and teachers sufficient—adequate or competent—to be ministers of the new covenant. When Paul uses the words "new covenant," he is contrasting their message of salvation through faith in Christ by God's grace with the Old Covenant message of salvation for Israel through following the law of Moses.
Paul adds that he and the others are not ministers of the letter, perhaps meaning the "letter of the law." In his old life as a Pharisee, Paul was a minister of the letter of the law, teaching Israelites to obey God's written words in the Old Covenant. Now, though, he has become a minister of the Holy Spirit. By this, he means that he teaches those who trust in Christ to live by the Spirit's power.
Paul adds that "the letter" kills. In other words, those who attempt to follow the law discover that they are unable to follow the law. They discover in themselves the sinfulness that keeps them from obeying God and condemns them to death. He put it this way in Romans 7:9–10, "I was once alive apart from the law, but when the commandment came, sin came alive and I died. The very commandment that promised life proved to be death to me."
God's Spirit, on the other hand, truly gives life to those who trust in Christ under God's new covenant with all of humanity. God's Spirit comes to live with all who believe in Jesus. His presence becomes the evidence that we belong to God. Romans 8:11 says, "If the Spirit of him who raised Jesus from the dead dwells in you, he who raised Christ Jesus from the dead will also give life to your mortal bodies through his Spirit who dwells in you."