Once there was shepherd who had 15 sheep. He would take them to grounds daily, for grazing and then in evening would bring back to their fence which was enclosed by barbed wire and would lock the fence entry from outside. Everything was going okay until one morning when shepherd was taking sheep out for grazing, he found that one sheep was missing. He thought that may be fence was broken but when he looked around he found out that fence was not broken. So there was no possibility of wild animals to come in from outside and attack sheep. Then shepherd turned to rest of sheep and asked, "Do you know sheep how disappeared from here? did something happen here at night?"All sheep waved their head in no. Shepherd couldn't find reason. He took sheep out for grazing like routine, he bought them back to fence and locked fence from outside. Next morning, when shepherd arrived, he was shocked to see that even today a sheep was missing. Shepherd tried to find reason but couldn't understand how and where sheep disappeared. He even tried asking other sheep but nothing was found. It started to happen continuously and everyday a sheep would disappear. Day came when only two sheep were left in the fence. Shepherd was very sad and disappointed and considered it his bad luck. He took remaining two sheep out for grazing and in evening put them back inside fence. As he was about to leave, a voice came from behind saying, "Wait, don't leave me alone, otherwise this wolf will kill me tonight."Shepherd immediately turned back and said, "Wolf! where is wolf?"Sheep pointing toward another sheep said, "He who stands in front of you is not a sheep but a wolf in skin of a sheep.when a sheep went missing for first time, I was not able to sleep that night because of fear. that night I saw that after midnight, this wolf under sheep skin, killed the sheep sleeping next to it."When wolf saw that his secret had been revealed, he tried to run away but shepherd hit it hard with stick until it became unable to move. Now, shepherd understood whole story and shouted at sheep asking, "When you knew this thing before, why didn't you tell me before when I asked?"Sheep replied, "I was scared seeing that wolf killing other sheep and didn't dare to speak truth. at that time I thought that may be wolf will leave after eating couple of sheep only.but today, am only one left and now I had only one option to save myself and that was to gather up my courage and tell you the truth. that's why I was able to tell you everything today."Shepherd said, "How did you thing that wolf will leave on it's own after killing one or two sheep! wolf is wolf, it cannot change its nature. just think how your silence gave wolf way to kill so many innocent sheep. if you had already shown courage to speak the truth, things would have been different.." 
Similarly, there are many occasions in life where a little courage can make a big difference but just like that sheep, most of us sit in silence until trouble comes to our heads. Therefore, we should learn to show courage to tell truth at right time and fight against wrong happening around us. 