Another narration
Nuʿaym ibn Ḥammād said: “Abū ʿAmr al-Baṣrī related to us, from Ibn Lahīʿah, from ʿAbd al-Wahhāb ibn Ḥusayn, from Muḥammad ibn Thābit al-Bunnānī, from his father, from al-Ḥārith al-Hamdānī, from Ibn Masʿūd, from the Prophet ﷺ, who said:

‘The seventh man descended from al-ʿAbbās will summon the people to disbelief, but they will not respond. His own household will say to him, “Do you want to strip us of our livelihoods?” He will reply, “I intend to govern you according to the way of Abū Bakr and ʿUmar.” They will refuse, and an enemy of his from his own family, one of the Banū Hāshim, will kill him. When that attacker strikes, they will fall into mutual discord.’

(It then goes on to describe a long period of internecine strife that lasts until the appearance of the Sufyānī.)

This ḥadīth applies to ʿAbd Allāh al-Maʾmūn, who called the people to affirm that the Qur’an is created—may Allah protect the ummah from that trial, as we shall detail in its proper place. The Sufyānī, who will appear at the end of time, is a man descended from Abū Sufyān; we shall discuss him at the close of the Book of Malāḥim.

Another narration
Imām Aḥmad said: Hāshim narrated to us; Layth narrated to us; from Muʿāwiyah ibn Ṣāliḥ, from ʿAbd al-Raḥmān ibn Jubayr, from his father, who said: I heard Abū Thaʿlabah al-Khushani, a Companion of the Messenger of Allah ﷺ, say—he was in al-Fuṣṭāṭ during the caliphate of Muʿāwiyah, and Muʿāwiyah was the one who dispatched the most expeditions against Constantinople—he said:

“By Allah, this ummah will not be hindered for more than half a day. When you see Syria serving as the table of a single man and his household, then know that Constantinople will be conquered.”

This is how Aḥmad narrated it, stopped at the statement of Abū Thaʿlabah. Abū Dāwūd recorded it in his Sunan through Ibn Wahb, from Muʿāwiyah ibn Ṣāliḥ, from ʿAbd al-Raḥmān ibn Jubayr, from his father, from Abū Thaʿlabah, who said that the Messenger of Allah ﷺ declared:

“Allah will not allow this ummah to be overcome for more than half a day.”

Abū Dāwūd alone transmitted this report.

Abū Dāwūd then said: ʿAmr ibn ʿUthmān narrated to us; Abū al-Mughīrah narrated to us; Ṣafwān narrated to me, from Shurayḥ ibn ʿUbayd, from Saʿd ibn Abī Waqqāṣ, that the Prophet ﷺ said:

“I hope that my ummah will not be found wanting before their Lord such that He defers them for only half a day.”

It was asked of Saʿd, “How long is half a day?” He replied, “Five hundred years.” Abū Dāwūd is alone in transmitting this ḥadīth, and its chain is sound.