Our fault in this matter.
(3) The duties are to be done in the spirit of hard toil.
The servant has 'his work' allotted him, and the word implies that the work calls for effort. The race is not to be run without dust and sweat. Our Christian service is not to be regarded as a 'bye-product' or parergon. It is, so to speak, a vocation, not an avocation. It deserves and demands all the energy that we can put forth, continuity and constancy, plan and system. Nothing is to be done for God, any more than for ourselves, without toil. 'In the sweat of thy brow shalt thou eat bread and give it to others.'
III, To do this work, watchfulness is needed.
The division of tasks between 'servant' and 'porter' is only part of the drapery of the parable. To show that watchfulness belongs to all, see the two following verses.
What is this watchfulness?
Not constant fidgety curiosity about the coming of the Lord; not hunting after apocalyptic dates. The modern impression seems to be that such study is 'watchfulness.' Christ says that the time of His coming is hidden (see previous verses). Ignorance of that is the very reason why we are to watch. Watchfulness, then, is just a profound and constant feeling of the transiency of this present. The mind is to be kept detached from it; the eye and heart are to be going out to things 'unseen and eternal'; we are to be familiarising ourselves with the thought that the world is passing away.
This watchfulness is an indispensable part of our 'work.' The true Christian thought of the transiency of the world sets us to work the more vigorously in it, and increases, not diminishes, our sense of the importance of time and of earthly things, and braces us to our tasks by the thought of the brevity of opportunity, as well as by guarding us against tastes and habits which eat all earnestness out of the soul.
Thus 'working and watching,' happy will be the servant whom his Lord will find 'so doing,' i.e. at work, not idly looking for Him. Our common duties are the best preparation for our Lord's coming.