The word disciple is closely associated with the word discipline, and it might well be said that a disciple is a disciplined believer or adherent. The word literally means “a learner” and denotes one who follows the teachings of another. A disciple, however, is not merely a pupil but is an imitator of the teacher. In the Jewish culture of Jesus’ day a disciple of a rabbi would leave his home and move in with his teacher. He served the teacher in the most servile ways, treating him as an absolute authority. He was expected not only to learn all that his rabbi knew but also to become like him in character and piety. In turn, the rabbi provided food and lodging and saw his own distinctive interpretations transmitted through his disciples to future generations. When Mark says that Jesus chose twelve men “that they should be with him” (Mark 3:14), he accurately reflects contemporary understanding of how future leaders were trained. Inherent in such a call was the idea of a disciple’s total commitment.
-W.E. Vine - An Expository Dictionary of New Testament Words, Pg. 226
