James 2:14 

What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him? 

In America, people use the word "Christian" to mean something totally different from what it means in the scriptures. In scripture, to be a Christian means to be "Christ-like" or "like Christ". The term "Christian" is first used in scripture in Acts 11:26, which says, "And when he had found him, he brought him unto Antioch. And it came to pass, that a whole year they assembled themselves with the church, and taught much people. And the disciples were called Christians first in Antioch."  It literally means that one closely associates himself with the person and character of the LORD Jesus Christ. By doing so, that person's life reflects the fact that they have submitted themselves totally and completely to Him. They behave in a manner that represents Christ well. Though not perfect, a true Christian has "works" that reflect his faith. His behavior, speech, temperament, appetites, thought process, and overall demeanor are based on his faith in Christ and his desire to please the LORD. Without such desire, it is questionable as to whether that person is truly a Christian.  No one can be a "Christian" and not reflect the change in his or her life.  2 Corinthians 5:17 says, "Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new."  Once a person is in Christ, there will be a change in him.  The old behaviors will begin to feel strange.  There are new thought processes and new desires.  No one can come to Christ and remain the same.

James lays it out for us pretty clearly. There is no profit in saying we have the faith in the LORD Jesus Christ if we never exhibit the fruit of His Holy Spirit. The LORD does not do anything half heartedly; He will not save us and then not give us His indwelling Spirit by which to live. When He gives us His Spirit, He gives us the power to be like Him.  We have the power to turn away from sin and walk after the Spirit of God (Romans 5:8, Galatians 5:16).  Believer, use that power today.