What then? Are we to sin because we are not under law but under grace? By no means! Do you not know that if you present yourselves to anyone as obedient slaves, you are slaves of the one whom you obey, either of sin, which leads to death, or of obedience, which leads to righteousness? But thanks be to God, that you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed, and, having been set free from sin, have become slaves of righteousness. —Romans 6:15-18
When you hear that God is sovereign and that he has guaranteed that those under grace will not be defeated by sin, do not jump to the conclusion that the battle is a charade, and nothing hangs on your choices. Don’t say, “Let us sin that grace may increase” (Romans 6:1). Don’t say, “Let us sin because we are not under law but under grace” (Romans 6:15). In other words, don’t come to the Bible with the assumption: if it does not depend on what I choose ultimately, it does not depend on what I choose at all. That is man-centered, unbiblical thinking. Rather say, “Since it depends on God ultimately, there is hope that I, a dead and hardened sinner, may choose what is good and live a life pleasing to the Lord. Let the sovereignty of God make you hopeful that change is possible, not passive as if no change were necessary.