Having called his men, Jesus made a practice of being with them. This was the essence of his training program—just letting his disciples follow him.
When one stops to think of it, this was an incredibly simple way of doing it. Jesus had no formal school, no seminaries, no outlined course of study, no periodic membership classes in which he enrolled his followers. None of these highly organized procedures considered so necessary today entered into his ministry. Amazing as it may seem, all Jesus did to teach these men his way was to draw them close to himself. He was his own school and curriculum.
The natural informality of this teaching method of Jesus stood in striking contrast to the formal, almost scholastic procedures of the scribes. These religious teachers insisted on their disciples adhering strictly to certain rituals and formulas of knowledge which distinguished them from others; whereas Jesus asked only that his disciples follow him. Knowledge was not communicated by the Master in terms of laws and dogmas, but in the living personality of One who walked among them. His disciples were distinguished, not by outward conformity to certain rituals, but by being with him, and thereby participating in his doctrine (John 18:19).
Coleman, Robert E. 2006. The Master Plan of Evangelism. Grand Rapids, MI: Revell.