Commentators explain that this verse contrasts two governing principles. "The law of sin and death" is the powerful, internal rule of our fallen nature that leads to death. In contrast, "the law of the Spirit of life" is the new, superior power of the Holy Spirit given to believers in Christ. This new "law" doesn't add rules; it imparts life and breaks the chains of the old one, acting as what one scholar called the "expulsive power of a new affection."