Muwatta Malik 201
موطأ مالك#201SahihThese are the words of a Companion, not of the Prophet ﷺ. The chain is graded on its own terms.
وَحَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّ الْقَاسِمَ بْنَ مُحَمَّدٍ، أَرَاهُمُ الْجُلُوسَ فِي التَّشَهُّدِ فَنَصَبَ رِجْلَهُ الْيُمْنَى وَثَنَى رِجْلَهُ الْيُسْرَى وَجَلَسَ عَلَى وَرِكِهِ الأَيْسَرِ وَلَمْ يَجْلِسْ عَلَى قَدَمِهِ ثُمَّ قَالَ أَرَانِي هَذَا عَبْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُمَرَ وَحَدَّثَنِي أَنَّ أَبَاهُ كَانَ يَفْعَلُ ذَلِكَ .
Yahya related to me from Malik from Yahya ibn Said that al-Qasim ibn Muhammad showed them how to sit in the tashahhud, and he kept his right foot vertical and laid his left foot down, and sat on his left haunch not on his foot. Then he said, "Abdullah ibn Abdullah ibn Umar saw me doing this and related to me that his father used to do the same thing
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 3:34