In this parable by Jesus about His Second Coming, He appealed to the disciples' sense of justice.  The story is about a man who sets up a business at his own expense.  He appointed a manager to direct and provide for the staff while he is away.  When the owner of the business returns the manager’s performance is assessed.  If that manager does his job well and respects the owner’s wishes, the faithful work will be rewarded.  However, if the manager has no respect for the owner, and behaved selfishly, and abuses the staff, the owner will not hesitate to punish the manager.  

In the story, the master of the household is Jesus, and the manager represents all who are given spiritual responsibility in Christ’s church (Hebrews 13:7; James 3:1).  (That principle may also have been intended to stretch back to the past spiritual leaders of Israel and include those who were currently plotting to kill Him.)  The heart-attitudes of these two managers are poles apart.  The point of the story is not that one behaviour is good and the other is bad, although that is true.  Jesus was teaching that those who are faithful to their commission always behave as though their master is watching them, whether they are being watched or not.  This is in sharp contrast to others who calculate that the master will never know what they do, and they do not care anyway.  
 
But the Lord knows everything.  He not only knows what we do, but why we do it: to glorify Him or to glorify ourselves.  It is that heart-attitude which is rewarded or punished – not how successful we are in doing our duty (Luke 17:10).  The servant with the unfaithful heart would be punished; hell is the place of eternal remorse with no relief.  However, both were equal in one matter: neither knew when their master would return.  But those who loved him acted as if he was with them all the time (Colossians 3:22-23), and so they were ready for his return (Titus 2:11-14).  However, the unfaithful servant was glad that his master was not there, and so his return was a dreadful shock which soon turned into an eternity of weeping and gnashing of teeth.
 
Jesus wanted the disciples, and the church they would teach, to want to please Him - whether He was present or not.  Paul applies this principle to the Christian in the workplace, "Slaves, obey your earthly masters with respect and fear, and with sincerity of heart, just as you would obey Christ. Obey them not only to win their favour when their eye is on you, but as slaves of Christ, doing the will of God from your heart. Serve wholeheartedly, as if you were serving the Lord, not people, because you know that the Lord will reward each one for whatever good they do ..." (Ephesians 6:5-8). Our attitude at work is a useful way to check how ready we are to meet the Lord!