I say: He is alluding to what he cited a page earlier, namely his words:

“And the last view that Mālik adopted—eleven rakʿahs—is supported by the report transmitted by Abū Yaʿlā from Jābir ibn ʿAbd Allāh, who said: ‘Ubayy ibn Kaʿb came to the Messenger of Allah ﷺ and said, “Messenger of Allah, something happened with me last night”—he meant during Ramadan. The Prophet asked, “And what was that, O Ubayy?” He replied, “Some women in my house said, ‘We do not recite the Quran; will you then lead us in prayer?’ So I led them in eight rakʿahs and then performed witr, and it became an approved Sunnah, for he raised no objection.”’”

Al-Haythamī remarks in Majmaʿ al-Zawāʾid: “Its chain is ḥasan.”

The second route: al-Ḍiyāʾ al-Maqdisī recorded it in al-Mukhtārah (1/384) through Abū Jaʿfar al-Rāzī, from al-Rabīʿ ibn Anas, from Abū al-ʿĀliyah, from Ubayy ibn Kaʿb, that ʿUmar ordered Ubayy to lead the people in prayer during Ramadan. ʿUmar said, “People fast by day and are not proficient in recitation; would you therefore recite the Quran to them at night?” Ubayy replied, “Commander of the Believers, this is something that has never been done.” ʿUmar answered, “I know, but it is good.” So Ubayy led them in twenty rakʿahs.

I say: This isnād is weak. This Abū Jaʿfar—whose name is ʿĪsā ibn Abī ʿĪsā ibn Māhān—was listed by al-Dhahabī in al-Ḍuʿafāʾ, and he said… ⦗79⦘