3:6 new covenant. The new legal relationship that God established with His people through Jesus Christ, His life, death, resurrection, and ascension.
the letter. The written law by itself, which demands perfect obedience but gives no power to obey.
the Spirit gives life. This is new life in Christ. In it the Holy Spirit writes God’s law on our hearts (Jer. 31:31–34; Heb. 8:8–12; 9:13, 14), giving love for God’s moral standards and power to obey them (Rom. 8:4; 1 Cor. 7:19). Saying that life is “not of the letter,” Paul does not imply that there was no spiritual life whatever under the old covenant. He means that the written law, which was characteristic of the old covenant, did not by itself produce life in the believing community. The Holy Spirit, whose powerful, life-giving ministry is characteristic of the new covenant, does bring new life in much greater measure than under the old covenant.