Believer vs. Disciple

An acquaintance e-mailed me last week and ask me to explain the complex differences between a believer in Jesus Christ and a disciple of Jesus Christ. To me, the answer couldn't be more simple.

Even the demons believe in Jesus Christ. So being a believer in Jesus only puts one on par with the demons. But a true disciple willingly obeys Jesus Christ. That is something the demon will never do!