The goodness of the Good Samaritan was not only his helpfulness to a man in need. Commentators have astutely pointed out that the Samaritan should have been the least likely to help, based on the ethnic preconceptions of the time. From this we learn that we should serve all people, independent of race or ethnicity or ideology. The message goes deeper than this, however.
The Samaritan was journeying like the others who passed the injured man, yet he alone paused his travelling to care for the wounded traveler. We cannot assume that his journey was any less important than the others', nor can we assume that he was in less of a hurry. We do know, however, that the Samaritan was open to an additional, unintended, higher calling, received as a rupture of intended purpose.
We live in a curious world, wherein efficient, rational action has extremely high moral value. We endlessly praise those who live rational and efficient lives, including those who maximize their time, who stay constantly focused on the task at hand, and who never get distracted by other voices. Admittedly, such people do tend to accomplish many great things.
Another version of the parable of the Good Samaritan is Charles Dickens' classic, A Christmas Carol. Recall the dialogue between Ebenezer Scrooge and the ghost of Jacob Marley, who, in his posthumous state of bondage, laments his mortal doings:
"But you were always a good man of business, Jacob," faltered Scrooge, who now began to apply this to himself.
"Business!" cried the Ghost, wringing its hands again. "Mankind was my business. The common welfare was my business; charity, mercy, forbearance, and benevolence, were, all, my business. The dealings of my trade were but a drop of water in the comprehensive ocean of my business!"
In order to live productive and meaningful lives we must engage in purposeful activity, but in doing so, we must take care to remember the business of which we are always about. Being Christlike requires more than rationally planning our activities and taking care to dedicate a certain number of hours to service. In all of our activities, be it planning, errand-running, administrating, teaching, parenting, conversing, or travelling, we must always remain open and responsive to the unanticipated calling to serve a higher purpose. This, I think, in addition to comprising the heart of the parable of the Good Samaritan, reflects the kind of life that Christ himself lived and preached.