What is the warning that the Prophet Muhammad (saw) gave regarding those who don't affirm belief in the message which he was sent with?
 It is narrated on the authority of Abu Huraira that the Messenger of Allah (may peace be upon him) observed:                      By Him in Whose hand is the life of Muhammad, he who amongst the community of Jews or Christians hears about me, but does not affirm his belief in that with which I have been sent and dies in this state (of disbelief), he shall be but one of the denizens of Hell-Fire.