Rashid bin Sa'd narrates: When Istakhr was conquered, a caller announced: "Beware! The Dajjal has emerged." The narrator says: Sayyiduna al-Sa'b bin Jaththamah (may Allah be pleased with him) met those people and said: You are saying this, so I tell you that I heard the Prophet (peace and blessings be upon him) say: "The Dajjal will not emerge until people have forgotten to mention him, and until the imams have abandoned mentioning him on the pulpits."
Abdullah bin Ahmad recorded it as a narration of Baqiyyah, which he narrated from Safwan bin Amr, and
this narration is sound, as Yahya bin Ma'in said, and the remaining narrators of this report are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الفتن - أعاذنا الله منها / 12499