This is call an a fortiori argument—one from a greater point to a lesser point. If Jesus can rid Mary Magdalene of her demons, then he can rid you of your sin problems.
If you were to interview people at Grace Community Church, you would discover former drug addicts, alcoholics, sex addicts, workaholics, arrogant, self-centered, egotistical people. The one key difference in their lives is Jesus Christ. You would discover people radically changed by Jesus Christ.
Whatever your problem is, it isn’t too big for God. Mary Magdalene’s case proves that.