What does Colossians 3:9 mean?
Verses 5 and 8 combine to give a ten-item list of worldly sins Christians should remove from their lives. These include sexual immorality, jealousy, revenge, slander, and so forth. In addition, Paul now speaks in detail against Christians lying to one another. Note that, in this particular case, Paul is specifically addressing Christians lying to fellow Christians. All believers, regardless of class, race, background, age, gender, or ability, are part of the same family (Colossians 3:11; Galatians 3:28). Rather than being petty or deceptive, believers are to treat one another well, speaking the truth in love (Ephesians 4:15).Paul's reason believers should not lie to one another is found in the issue of identity. Those who put a trusting faith in Christ are new people who have died to sin and have become alive in Christ. The goal is then to live a Christ-like life. Lying to one another is inconsistent with this new life. Paul supports this argument by appealing to the highest authority possible: Christ Himself. The old self, of sin and the world, is contrasted with the new self in verse 10. The idea of the "old self" is also discussed by Paul in Romans 6:6 and Ephesians 4:22.