On the day of Siffin, a man from the people of Sham called out, "Is Uways al-Qarani among you?"They said, "Yes."He said, "I heard the Messenger of Allah ﷺ say, 'Among the best of the Followers is Uways al-Qarani.'"
حدثنا أبو نعيم قال حدثنا شريك عن يزيد بن أبي زياد
نادى رجل من أهل الشام يوم صفين أفيكم أويس القرني قالوا نعم قال سمعت رسول الله ﷺ إن من خير التابعين أويسا القرني
No references are available.
Its isnad is daif, because of Ziyad bin Abu Ziyad, but the hadith is sahih. Muslim narrated something similar to it, 4/1968, no. 2542, in the Virtues of the Companions, the virtues of Uways Qarani. It is also found in Hakim with a similar wording, 3/402. It has already appeared at the beginning of the Musnad, no. 266, in the Musnad of Umar bin Khattab.