Obedience is important. It demonstrates the value you place on your commander as well as on the command. Paul, as an Apostle, had the right to command obedience to the gospel. Christians are not only to respond with joy at the knowledge of sins forgiven; but if they value Jesus and all that He has done, they should reject disobedience and put everything into pleasing Him (Titus 2:12). The Philippian church had started well, while Paul was with them, and he has now heard good reports of their faithfulness to Christ: but they need to keep going, whatever the cost (2 Timothy 3:14).