Romans 6:14 For sin shall not have dominion over you: for ye are not under the law, but under grace.
Why is it the fact that being under grace instead of law has the effect that sin no longer has dominion over us?
Because, as Paul makes so clear in chapter 1 of Romans, sin is the consequence of our rebellion against God and our refusal to worship Him as God. We are “given over” to sin as a consequence. So far from being able to work our way out from under the covenant of law, the very sins we commit, part of the consequence for Adam’s rejection of that covenant, continue to condemn us under the terms of that covenant, resulting in more punishment, which includes more sin. So it’s hopeless.
We recognize then that grace, forgiveness in the blood of Jesus Christ, is the only way to get out from under that. And part of the result then of accepting the grace of Jesus Christ is that we will be released from the penalty of the covenant of Law, which means that sin will have no more dominion over us.
The believer continues to struggle with sin all of his life, as he realizes and lays hold of the effects of this salvation. The Holy Spirit applies the results of this salvation to us and the result is sanctification. Sin no longer has dominion over us.
And this shows the great foolishness of any that would say that the doctrine of justification by faith alone results in more sin; that statement demonstrates a complete failure to understand what sin is. On the contrary, any attempt to accomplish righteousness by works will result in more sin, since trying to accomplish righteousness by works is to operate according to the covenant of works, which requires perfection. And the failure to keep the covenant of works results in the penalty of that covenant being applied, part of which is being given over to vile affections.
Paul goes on to make this point in Romans 6. We are the servants of whom we obey, either of righteousness unto life, or of sin unto death. Being bought out of the covenant relationship of law, we are freed from obedience to that cruel taskmaster, which because of our failure would have destroyed us in sin and death. We are now bought into the relationship of grace, enabling us to begin to live righteously as we move toward eternal life in that covenant, which is characterized by perfect righteousness. Obeying our new master, grace and forgiveness, results in righteousness and life.