Sunan Abi Dawud 961
سنن أبي داود#961Sahih(There is another chain) from Yahya bin Sa'eed that Al-Qasim bin Muhammad saw them sitting in Tashah-hud, so he mentioned the Hadith
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih
In-book reference: 2:572