Romans 5:21

Unto death. Rather, “in death,” death being, as it were, the sphere or dominion in which the sovereignty of sin is exercised (cf. verses 14, 17). Sin reigns over a kingdom of death.

Grace reign. Grace (see on chapter 3:24) is here personified as were sin (see on chapter 5:12) and death (see on verse 14).

Righteousness. That is, Christ’s righteousness imputed in justification and imparted in sanctification (see on chapters 3:31; 4:8).

By Jesus Christ. Paul began this chapter by describing the joy and assurance that come to the believer who has accepted justification by faith in Jesus Christ. This led him to speak of the greatness of God’s love and grace in making possible so generous a plan to save undeserving sinners. Then, to magnify God’s love and grace as the basis of the Christian’s hope and confidence, Paul proceeded to contrast the exceeding abundance and power of God’s saving grace through Jesus Christ with the sinfulness and degeneracy of man resulting from Adam’s fall. God has made ample provision to meet all the dire results of man’s great apostasy.