صَحِيحُ مُسْلِمٍ
Sahih Muslim 580 b
The Book of Mosques and Places of Prayer
The description of the sitting during the prayer, and how the hands are to be placed on the thighs
وَحَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، حَدَّثَنَا يُونُسُ بْنُ مُحَمَّدٍ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا قَعَدَ فِي التَّشَهُّدِ وَضَعَ يَدَهُ الْيُسْرَى عَلَى رُكْبَتِهِ الْيُسْرَى وَوَضَعَ يَدَهُ الْيُمْنَى عَلَى رُكْبَتِهِ الْيُمْنَى وَعَقَدَ ثَلاَثَةً وَخَمْسِينَ وَأَشَارَ بِالسَّبَّابَةِ .
Another version on the authority of Ibn Umar says: When the Messenger of Allah (ﷺ) sat for tashahhud, he placed his left hand on his left knee and placed his right hand on his right knee, and he formed a ring like (fifty-three) and pointed with his finger of attestation.
Sahih Muslim, 580 bSahihصحيح