Romans 6:1-2 KJV
What shall we say then? Shall we continue in sin, that grace may abound?
God forbid. How shall we, that are dead to sin, live any longer therein?
The phrase "How shall we" means "in what way" or "by what manner". The message is that it can't be done. There is no open road. There is no road at all. Just as medical science, then and now, has no way of bringing to life that which is dead, there is no possibility of the believer using grace in order to live in sin. It is an incompatible concept for the truly saved person to justify sin with grace. Every Christian sins. When we sin we depend upon the grace of God and are thankful for it. But true Christians could and would never expect that grace makes a way to sin.
The believer sees grace as the way to righteousness, holiness and separation from the nature of sin that dwells in him. He looks at the death, burial and resurrection of Christ as his escape from sin and not his excuse to sin. When he does sin, he comes boldly to God for mercy and rests in the grace of God. He does not revel in unrighteousness and exploit God's grace.