Jesus replied, "A man was going down from Jerusalem to Jericho, and fell into the hands of robbers, who stripped him, beat him, and went away, leaving him half dead.  Now by chance a priest was going down that road; and when he saw him, he passed by on the other side.  So likewise a Levite, when he came to the place and saw him, passed by on the other side.  But a Samaritan while traveling came near him; and when he saw him, he was moved with pity.  He went to him and bandaged his wounds, having poured oil and wine on them.  Then he put him on his own animal, brought him to an inn, and took care of him.  The next day he took out two denarii, gave them to the innkeeper, and said, 'Take care of him; and when I come back, I will repay you whatever more you spend.'  Which of these three, do you think, was a neighbor to the man who fell into the hands of the robbers?"  He said, "The one who showed him mercy." Jesus said to him, "Go and do likewise."

As I began reading this passage I thought: "We could easily say here, especially if we had known this man, 'why do terrible things happen to people?  Why does God allow it?'"  Here we even have God himself relating a story about an evil which befell someone, but not for the purpose of explaining evil in the world.  Jesus tells the story to show how we must give mercy to one another.  Bad things which happen to people are invitations for us to show mercy toward them.  It is how we will be judged, it is how we learn that love without which we cannot enter the kingdom of Love.  Finally, showing mercy to others after bad things have happened also includes mercy toward ourselves.