What did the Prophet Muhammad (peace be upon him) warn about Ad-Dajjal and why was it so significant?
      Narrated Ibn Umar:                          (Later on) Allah's Apostle (once again) went along with Ubai bin Ka'b      to the garden of date-palms where Ibn Saiyad was staying. When the      Prophet entered the garden, he started hiding himself behind the      trunks of the date-palms as he wanted to hear something from the Ibn      Saiyad before the latter could see him. Ibn Saiyad was lying in his      bed, covered with a velvet sheet from where his murmurs were heard.      Ibn Saiyad's mother saw the Prophet while he was hiding himself behind     the trunks of the date-palms. She addressed Ibn Saiyad, "O Saf!" (And      this was his name). Ibn Saiyad got up. The Prophet said, "Had this      woman let him to himself, he would have revealed the reality of his      case." Then the Prophet got up amongst the people, glorifying Allah as     He deserves, he mentioned Ad-Dajjal, saying, "I warn you about him      (i.e. Ad-Dajjal) and there is no prophet who did not warn his nation      about him, and Noah warned his nation about him, but I tell you a      statement which no prophet informed his nation of. You should      understand that he is a one-eyed man and Allah is not one-eyed."