Apostle vs. Disciple: Whats's the difference?

The difference is that a disciple is a student while the apostle is a messenger. One learns from a master or teacher; while the other is sent to deliver these teachings of the master to others. Every apostle must have been a disciple to know the message to deliver, but not every disciple is an apostle. In Acts 1:21-22, it was stated that an apostle must have been one of Jesus Christ disciples and must have witnessed his resurrection. However, this was modified when Jesus Christ later called Paul. Though Paul wasn't part of Jesus Christ disciples while he was on earth, he grew in the word under the influence of the holy ghost.