Sahih Bukhari Volume 005, Book 059, Hadith Number 685.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 59. Military Expeditions Led by the Prophet (PBUH) (Al-Maghaazi)
Narrated By Ibn Umar : We were talking about Hajjat-ul-Wada, while the Prophet was amongst us. We did not know what Hajjat-ul-Wada' signified. The Prophet praised Allah and then mentioned Al-Masih Ad-Dajjal and described him extensively, saying, "Allah did not send any prophet but that prophet warned his nation of Al-Masih Ad-Dajjal. Noah and the prophets following him warned (their people) of him. He will appear amongst you (O Muhammad's followers), and if it happens that some of his qualities may be hidden from you, but your Lord's State is clear to you and not hidden from you. The Prophet said it thrice. Verily, your Lord is not blind in one eye, while he (i.e. Ad-Dajjal) is blind in the right eye which looks like a grape bulging out (of its cluster). No doubt,! Allah has made your blood and your properties sacred to one another like the sanctity of this day of yours, in this town of yours, in this month of yours." The Prophet added: No doubt! Haven't I conveyed Allah's Message to you? " They replied, "Yes," The Prophet said thrice, "O Allah! Be witness for it." The Prophet added, "Woe to you!" (or said), "May Allah be merciful to you! Do not become infidels after me (i.e. my death) by cutting the necks (throats) of one another."