It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "I am Ahmad, I am Muhammad, I am al-Hashir (the Gatherer), I am al-Muqaffi (the one who came after the others), and I am al-Khatam (the Seal)."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from al-Dahhak except Salamah bin Nubayt, and Abu Nu'aym is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الألف / 2280
Hadith Takhrij«أخرجه الطبراني فى «الصغير» برقم: 156»