A license to sin. Men are sinners naturally. You don't need a license to do what comes naturally. God justified the ungodly by grace. The point is what God has done through Christ. He forgave all sins and cleanses from all sin.Col 2:13
And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses;
And for the forgiven God does not imputed sin Ron 4:7-8
Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered.
8 Blessed is the man to whom the Lord will not impute sin.
Do you know the reason for being born again? Do you know that without the power of the Holy Spirit indwelling you, you don't belong to Christ? Do you know the purpose of the Holy Spirit? Do you know that without holiness, no man shall see God?
You really need to read past the 4th chapter of Romans. For one thing, Paul's teaching is 8 chapters long, from chapter one through 8. Read it in one sitting because Paul builds onto each chapter. You've stopped at we are not under the law, but that does not mean we are lawless. Chapter 6 will show you how wrong you are. The law could not make us righteous. That was the Old Covenant. The New Covenant laws go deeper to the core of our being, and the Spirit empowers us to fulfill the righteous requirement of God's eternal laws.