2 Corinthians
King James Version (KJV)

“Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.”
King James Version (KJV)
3:6 Who also hath made us able ministers of the new covenant - Of the new, evangelical dispensation. Not of the law, fitly called the letter, from God's literally writing it on the two tables. But of the Spirit - Of the gospel dispensation, which is written on the tables of our hearts by the Spirit. For the letter - The law, the Mosaic dispensation. Killeth - Seals in death those who still cleave to it. But the Spirit - The gospel, conveying the Spirit to those who receive it. Giveth life - Both spiritual and eternal: yea, if we adhere to the literal sense even of the moral law, if we regard only the precept and the sanction as they stand in themselves, not as they lead us to Christ, they are doubtless a killing ordinance, and bind us down under the sentence of death.
2Co 3:6 Who also hath made us able ministers. God gave Paul and his fellow-ministers their "sufficiency" (2Co 3:5), who had made them able ministers of the gospel. Of the new testament. The New Covenant, the Covenant of Christ. This is here contrasted with the Old Covenant, the Jewish. One is the Law; the other the Gospel. Compare Heb 8:7-13. Not of the letter, but of the spirit. The first, the law, was written (by letters written and engraved on stones, hence "of the letter"); the gospel is the dispensation of the Spirit. The letter killeth. The law. It condemns all who do not obey its commands, but could make no man perfect. The law places under the sentence of death. See notes on Ro 7:9,10. The spirit giveth life. The gospel bestows eternal life.