The following three books are recommended:
Pure Grace: The Life Changing Power of Uncontaminated Grace. Clark Whitten
We have been freed from sin, and we cannot be transformed by trying to manage sin by human effort.The Rest of the Gospel: When the Partial Gospel Has Worn You Out. Dan Stone and David Gregory
We are called to be saints, not sinners, as we live "above the line" in the unseen realm, where we have been declared perfect, rather than "below the line" in the seen realm, where we are in the natural.Transformation: The Heart of Paul's Gospel. David A. DeSilva and Michael F. Bird
Paul's gospel is one of transformation and not one of justification - then looking for something to do.These books explain spiritual concepts much more clearly and use a less confrontational approach.
Some blogs are also recommended: