Friend, if you are a believer, you are not under Law, but under grace, therefore sin no longer has mastery over you. Your new identity is that you are under grace and therefore not mastered by sin.
When Jesus died to sin you died to the Law. Romans 7:4 NIV says, “So, my brothers and sisters, you also died to the law through the body of Christ…” You are not under God’s law, which means you are free from its judgment, condemnation, and punishment. You are now under grace which frees you from sin’s mastery and enables you to live to God in holiness.
Think of what this means. Under the Law you were locked up in sin, kept in sin’s prison, bound by the chains of sin. Sin was your master, and you obeyed its every demand. When it told you to view pornography you followed. When it said to sex chat on the Internet, or to commit sexual impurity, you obeyed.
But now, under grace, you have been forgiven, pardoned and set free. Under grace, you have been rescued from darkness, redeemed from sin and ransomed from death. Under grace you have been brought near, though you were once far away, and you are now loved and cherished.
There is a perfect illustration of this in Romans 7:1-6. It tells us what our time under the Law was like by using the analogy of a woman (us) married to a harsh husband (the Law). He makes continual demands on her that she’s unable to obey. He requires her to be perfect in all areas but doesn’t lift a finger to help her. He continually judges her every move, condemns her often and punishes her. He is harsh and demanding.
And this is what it is like to be under the Law. It demands perfection, judges our every thought and action, doesn’t provide an ounce of help, condemns us to hell and would punish us eternally.
But if the woman’s harsh husband were to die, she is released from the law of marriage and is free to marry another. Notice how Romans 7 words this:
Romans 7:4 NIV So, my brothers and sisters, you also died to the law through the body of Christ, that you might belong to another, to him who was raised from the dead, in order that we might bear fruit for God.