ISLAM PROHIBITS KILLING OF INNOCENT HUMAN BEINGS that whoever kills a human being, unless it be for murder or for couseing mischief in the land, it is as though he has killed all of mankind and whoever saves alive, it is as though he saved the whole of mankind quran 5:32.
Hazrat Muhammad(peace be upon him) was the best example. He forgave the woman that poisoned him, he impeded his followers to take revenge on the Meca people when he finally got into the city. He took compassion and forgiveness to the last step and God blessed him for that. We should do the same, for as Gandhi once said "eye per eye can do nothing but make this world blind".