Knowing that you are completely forgiven destroys the power of sin in your life.
We are not forgiven because we are good. We are forgiven because Christ bore our sins.
God does not leave you wondering whether you are saved or not. He tells you outright that you are His and that nothing can ever separate you from the love of Christ. Not even sin because His blood is greater than your sin!
The gospel of grace is not the license to sin. On the contrary, it is the power for them to sin no more!
Grace isn't a license to sin; it's a license from sin.