We used to count, while the Messenger of Allah ﷺ was alive and his companions were plentiful, Abu Bakr and Umar and Uthman, then we would stop.
حدثنا أبو معاوية حدثنا سهيل بن أبي صالح عن أبيه
كنا نعد ورسول الله ﷺ حي وأصحابه متوافرون أبو بكر وعمر وعثمان ثم نسكت
Its isnad is sahih. Suhayl bin Abu Salih, his trustworthiness was already established at 3916. His father, Abu Salih, whose name was Zakwan Samman Zayyat, was a trustworthy successor. Ahmad said, "Trustworthy, trustworthy, one of the most excellent and most trustworthy of people." Bukhari gave his biography in al-Kabir, 2/1/238.The hadith was narrated by Tirmidhi, 4:322-323, through the route of Ubaydullah bin Umar, from Nafi, from Ibn Umar, without the closing words "then we would fall silent." Tirmidhi said, "The hadith is hasan sahih gharib from this route. It is considered gharib as a hadith of Ubaydullah bin Umar, and this hadith has been narrated through more than one route from Ibn Umar."Bukhari also narrated it, 7:14, through the route of Yahya bin Saeed, from Nafi, in similar wording. He narrated it again, 7:47, through the route of Abdul-Aziz Majishun, from Ubaydullah, from Nafi, with the closing words, "then the companions of the Prophet ﷺ left off, we do not give preference to one over another." Hafiz pointed out, in the first location, to the various narrations of this hadith.Something similar in meaning will come later through another route, in a longer form, at 4797.