I was with the two of them in that gathering, but I was young and did not retain the hadith.The two of them said, "A man asked him about the witr prayer," and he mentioned the hadith, saying that the Messenger of Allah ﷺ commanded that the witr be made the final prayer of the night.
حدثنا يعقوب حدثنا أبي عن ابن إسحاق حدثني محمد بن إبراهيم بن الحارث عن أبي سلمة بن عبد الرحمن بن عوف وسليمان بن يسار كلاهما حدثه
ولقد كنت معهما في المجلس ولكني كنت صغيرا فلم أحفظ الحديث قالا سأله رجل عن الوتر فذكر الحديث وقال إن رسول الله ﷺ أمر أن تجعل آخر صلاة الليل الوتر
No references are available.
Its isnad is sahih. Muhammad bin Ibrahim bin Harith bin Khalid Taymi, his reliability was established earlier at 1778, and we add here that in Tahdhib it states he narrates from Ibn Umar and Ibn Abbas, according to what has been said, and it also states that Ibn Hibban said he heard from Ibn Umar. Bukhari gave his biography in Al-Kabir 1/1/22-23 and narrated from him that he said, "When I recited the Quran while I was a young man, I devoted myself to the masjid. I used to pray beside the path that the family of Umar bin Khattab took to the masjid, and I would see Abdullah bin Umar come out when the sun had passed its zenith and pray twelve rakats, then sit down. One day I came to him and he asked me who I was. I told him my lineage, and he said, 'Your skin shows you are from the emigrants to Abyssinia.' The people then praised me favorably." Among them was Sulayman bin Yasar, the freedman of Maymuna bint Harith, who was mentioned earlier at 1812, and we add here that he was one of the seven jurists. Abu Zura said, "Trustworthy, dependable, virtuous, devout." Bukhari gave his biography in Al-Kabir 2/2/42-43.The meaning of this hadith has occurred repeatedly through other routes, including at 6008 and 6171.