When I become a Christian, what I am doing is trusting in the sinless life of Christ and the punishment of Christ as the basis of my relationship with God instead of my behavior, my effort, my trying harder. And then, just as I am depending on the life and death of Christ for a relationship with God, so God is depending on the life and death of Christ for a relationship with me! He sees Christ’s sinless life as mine and Christ’s punishment as mine and so is as pleased with me as He is with his son. He declares me to be righteous.
For this we are thankful…deeply thankful. We express this thanks regularly. Many would say this is why we obey…we obey because we are so thankful. Our motivation is rooted in a feeling, in an attitude.
I believe we have a more significant and reliable source of obedience…and that is a transformed heart. Romans 6:17 talks about how we are not who we used to be, slaves to sin, but now we “have become obedient from the heart.” (ESV) We have a heart that can obey and wants to obey. Obedience is no longer just rooted in a thankful attitude, but in a new heart!