Prophet Muhammed (pbuh) forgave the pagans of Mecca (after he had taken it over) who had previously waged war on him and killed/tortured Muslims. He held peaceful debates with Christians in Mosques, gave charity to non-Muslims and forgave those who insulted him, the list goes on and on. These are just things the Prophet Muhammed (pbuh) did, and ISIS never has done. As for your question, ISIS burnt people alive, the Prophet (pbuh) never did. ISIS killed non-Muslim journalists who were given protection by Muslims, Muhammed (pbuh) never would kill anyone whom a Muslim has vouched for them. etc etc Shall we now compare ISIS to your Old Testament and put that question back to you?