Theissen1 wants to place this leaving everything
into a sociological context: in first-century Palestine the time had come for many impoverished members of the middle class to break out in one way or another (asceticism; guerrilla; etc.) from the normal community setup. Younger people also were susceptible to this. But Theissen compares things that are not comparable. The religious root is with the disciples not just one of the roots, but the decisive one. Moreover, they did not belong to the impoverished middle class but to the middle class of tradespeople with sometimes flourishing businesses (e.g., the family business of Zebedee).2
28 Peter began to say to him, “See, we have left everything and followed you.”