The Book of Mosques and Places of Prayer
كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
Read the English translation first, with the original Arabic directly underneath.
The description of the sitting during the prayer, and how the hands are to be placed on the thighs
'A'isha reported:
Umm Habiba and Umm Salama made a mention before the Messenger of Allah (ﷺ) of a church which they had seen in Abyssinia and which had pictures in it. The Messenger of Allah (ﷺ) said: When a pious person amongst them (among the religious groups) dies they build a place of worship on his grave, and then decorate it with such pictures. They would be the worst of creatures on the Day of judgment in the sight of Allah.
إِنَّ أُولَئِكِ إِذَا كَانَ فِيهِمُ الرَّجُلُ الصَّالِحُ فَمَاتَ بَنَوْا عَلَى قَبْرِهِ مَسْجِدًا وَصَوَّرُوا فِيهِ تِلْكَ الصُّوَرَ أُولَئِكِ شِرَارُ الْخَلْقِ عِنْدَ اللَّهِ يَوْمَ الْقِيَامَةِ