Sunan At-Tirmidhi

Abu 'Ubaidah bin Al-Jarrah said:""I heard the Messenger of Allah(s.a.w): 'There was never a Prophet after Nuh but that he warned his people about the Dajjal, and indeed I shall warn you of him.' Then the Messenger of Allah(s.a.w) described him for us, and he said: ""Perhaps some of you who see me, or hear my words shall live to see him."" They said: ""O Messenger of Allah! How will our hearts be on that day?"" He said: ""The same – that is, as today – or better.” (Hasan)