Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
abudawud:961 – al-Qaʿnabī > Mālik > Yaḥyá b. Saʿīd

(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.  

أبو داود:٩٦١ – حَدَّثَنَا الْقَعْنَبِيُّ عَنْ مَالِكٍ عَنْ يَحْيَى بْنِ سَعِيدٍ

أَنَّ الْقَاسِمَ بْنَ مُحَمَّدٍ أَرَاهُمُ الْجُلُوسَ فِي التَّشَهُّدِ فَذَكَرَ الْحَدِيثَ