From Sahih Muslim (Hadith 386):
It is narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) 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
Reference: Muslim 386