We are told in Luke 17:5 that the apostles responded to Jesus, which may imply that there was a greater crowd of disciples listening to Jesus in Luke 17:1. The apostles seem to have thought Jesus command to forgive repeatedly, no matter how often they were treated badly by folks, required a greater faith that they had. Yet, in Luke 17:6 Jesus told them and the others listening to him that the degree of one’s faith is not a matter of importance. Rather, the act itself—i.e. acting in faith—is the thing that is needed.
If the apostles’ faith were as small as a single grain of mustard seed, it would be no more powerful than if it were ten thousand times as large. Faith (trust) requires action. The apostles would be required to step out in faith no matter how great or small that faith might be. The point is, if faith is needed at all, men are unable to fill the requirement of the command in their own power. The power of God, on the other hand, is unlimited. If one steps out in the faith the size of a grain of mustard seed, he is brought just as far as the one whose faith is ten thousand times as large. It is the power of God, not the power of man, that is able to obey the command to repeatedly forgive the wrongdoing of others, and the need for faith implies man is unable to perform the task on his own.
The apostles weren’t taking into consideration that the power of God is unlimited. They still had their eyes fixed upon their own efforts (Luke 17:6). They wrongly assumed that greater faith would be enough for their lack of ability. Only the existence of faith matters. The amount of faith is unimportant, because it is the power of God that enables man to perform the task commanded. God requires faith before he will act, but the amount of faith is inconsequential, because God is enough for the smallest and the greatest of tasks.
To illustrate his point, Jesus taught the disciples from a story taken out of everyday life, which concerned the relationship between a master and his servants (Luke 17:7-10). In the context of the first century AD, the servant served his master from sunrise to sunset and continued to serve him while he ate his evening meal. It was his responsibility to do all that his master told him to do. Only then was he able to satisfy his own desires (Luke 17:7-8, 10).
According to the customs of the day, no matter how faithful a servant might be to his master, it was his duty to perform what he did. He wasn’t thanked for his faithfulness to his duties. After all, he did only that which was normally required of any servant.
Only we in these modern times would look back upon the customs of the first century AD and consider them unjust. The servant’s duty was to serve, and he didn’t have much time to himself. He had time to eat and sleep, and he rested on the Sabbath. Until our modern labor unions were formed, factory workers labored 16 hours a day and had 8 hours to eat and sleep. Men working on the open range in 19th century America weren’t much different. They worked all day and sometimes even into the night, when emergencies dictated. One didn’t have to be a slave to have to work long hours. This is simply how life was lived by most people around the world. Jesus didn’t come to change social mores. Rather, he came to change the hearts of men. Once men’s hearts were turned toward God, they would change their own social mores to imitate the loving and merciful manner in which each man is treated by God.
What could a man possibly give up in order to be considered a profitable servant? All he had were the times he had for eating and sleeping. If he gave that time up, he couldn’t have been profitable for long. He would have wasted away and died of want. What good would that have done him or his master? No, a servant’s whole duty was to serve his master, whoever that might be. When he had accomplished that, he had done his duty, and, if that is all one could say about him, he was by definition an unprofitable servant. So, in the context of Jesus’ command to forgive, Jesus’ disciples must do as they are told to do and forgive those who repeatedly wronged them (Luke 17:3-4) in an effort to win friends for Christ (Luke 16:9).