"Paul realised that his unqualified presentation of the grace of God left him open to being misunderstood. Paul himself knew that his insistence on the pure grace of God without any admixture of commitment or discipline or obedience on our part could cause us to misunderstand him. He knew his readers could respond with this attitude; "Well if that's true, let's go out and sin all we want. The more we sin, the more we cause God's grace to abound".
This type of response is always a possibility. In fact if our concept of grace does not expose us to that possible misunderstanding then we do not throughly understand grace. I believe it is because we are afraid of this attitude that we often change the doctrine of grace into a doctrine of works".
Jerry Bridges - "Transforming Grace - Living Confidently in God's Unfailing Love" - Navpress (1991) - (p74).