Muhammad (peace be upon him) taught many important principles and morals, and even set forth rules for combat setting the precedent and still exceeding the rules of war set forth by the Geneva Convention. Consider the following: All innocent life was sacred and as such none could be harmed, except those who were engaged against them in active combat. Saving one life was as if one had saved the entire world, while taking an innocent life was as if one had taken the lives of the entire world. There was to be no genocide of any tribes even up until some had committed genocide against some Muslims. He offered mutual protection and forgiveness to the all even after certain ones broke their covenants with him many times. He did not allow them to be attacked until it was clearly proven they were traitors during time of war and tried to bring down the prophet (peace be upon him) and the Muslims at any cost. Retaliation was only to those Jews who had turned traitor and not others. Slaves were common in those days for all nations and tribes. It was Islam that encouraged freeing of the slaves and the great reward from Allah for those who did so. Prophet (peace be upon him) gave the example of this by freeing slaves and encouraging all of his followers to do the same. Examples include his own servant (who was actually considered like a son to him) Zaid ibn Al Haritha and Bilal the slave who was bought by Abu Bakr only for the purpose of freeing him.