That was the question I got asked today. It is quite thought provoking. I started asking myself, what is the difference between one that was called by the Master to work in the vineyard and the one that simply volunteered.
Well the one called and who obeyed the call is liable to obey without hesitation whatever instruction he or she is given. But the one that volunteered can decide when he or she feels it is convenient to render the expected service.
A paid labourer is most likely to be more obligated to see a task through than a volunteer. I'll like to hear your view.