Though often people will reflect upon the story of the Good Samaritan in a manner critical of the priest and the Levite who refused to help the injured man, it may be fruitful if we try to think of things through their point of view. We might find a more profound lesson in the parable than we might initially have thought.
To my mind, there is no reason to suppose that the priest and the Levite were necessarily malicious. They need not have ignored or refused to help the fallen man out of incorrigible ill will or heinous malevolence. On the contrary, perhaps they had perfectly reasonable motives for not helping him -- so reasonable, in fact, that we may have to admit that we would have done the same.
In the first place, this is obviously a dangerous stretch of road. After all, our story begins with a robbery and mugging that nearly results in the death of one of the main characters! The priest and the Levite may have thought to themselves that if they stop here and help, they too might suffer just as bad or an even worse fate. Perhaps the fallen man was merely a trap laid for a greater ambush; perhaps the fallen man was a member of a gang who would just as soon pounce upon the priest or the Levite if they were to try to help.
Perhaps, too, the priest and the Levite had families at home for which they needed to provide, families which utterly depended upon them. To put their own lives at risk meant risking the lives of their children and wives. In such uncertain conditions, could anyone expect you to risk your life and your livelihood and the health of your family?
Yet the ultimate suggestion of the parable is that the priest and the Levite failed to live up to the commandment, Thou shalt love thy neighbor as thyself. They may have been perfectly "within their rights" not to stop to help; if they were to speak to us and tell us a bit about their motives, we might be inclined to sympathize with them. How many times do we go out of our way and utterly risk our lives to help a person who is in desperate need, even though such cases are all around us? Still, Jesus insists that these persons did not fulfill the commandment to love their neighbor.
Love has to go beyond the bounds of what is reasonable, of what can be expected a person. Love takes giant risks, risks to self, in order to provide for and help the person in desperate need. Jesus exemplifies this love perfectly when he willingly undertakes death for the salvation of the whole world -- even though it is unreasonable, even though nobody could ask such a thing of him, even though it was utterly reckless and irrational, even though the world did not deserve it.