This Hadith is telling: Bukhari:V5B59N314-7 "At Badr, the Prophet ordered the corpses of twenty-four Quraysh leaders to be thrown into a pit. It was a habit of the Prophet that whenever he conquered some people, he used to stay at the battlefield for three nights [to gloat]. So, on the third day he ordered that his she-camel be saddled and he set out. His Companions followed, saying: 'The Prophet is proceeding for some great purpose.' When he halted at the edge of the pit, he addressed the corpses of the Quraysh infidels by their names, 'O so-and-so, son of so-and-so! Why didn't you obey Allah's Apostle? I have found true what my Lord promised me. Have you found true what your Lord promised you.' Umar said, 'O Apostle! You are speaking to the dead.' Muhammad said, 'Allah brought them to life (again) to let them hear me, to reprimand them, to slight them, and so that I might take my revenge over them.' Then he quoted the Holy Verse out of the Qur'an: 'You cannot make the dead listen or the deaf hear your call...until they believe Our Signs and come into submission. [Qur'an 30:52] Both prophet and his spirit needed men to obey; they required full and unquestioned submission. That, in a nutshell, was what Islam was all about.