newness
Compare (Romans 2:29); (2 Corinthians 3:6).
"The letter" is a Paulinism for the law, as "spirit" in these passages is his word for the relationships and powers of new life in Christ Jesus. In 2 Corinthains 3, a series is presented of contrast of law with "spirit," of the old covenant and the new. The contrast is not between two methods of interpretation, literal, and spiritual, but between two methods of divine dealing: one through the law, the other through the Holy Spirit.