حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ الزُّبَيْرِ حَدَّثَنَا هِشَامٌ يَعْنِي ابْنَ سَعْدٍ عَنْ نَافِعٍ عَنْ ابْنِ عُمَرَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ رَأَى رَجُلًا سَاقِطًا يَدَهُ فِي الصَّلَاةِ فَقَالَ لَا تَجْلِسْ هَكَذَا إِنَّمَا هَذِهِ جِلْسَةُ الَّذِينَ يُعَذَّبُونَ
مسند امام احمد بن حنبل · Hadith 5972
It was narrated from Ibn 'Umar that the Messenger of Allah (PBUH) saw a man sitting with his hands on the floor (instead on his thighs) when praying, he said: "Do not sit like this; this is how those who will punished sit."
Sanad
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ الزُّبَيْرِ حَدَّثَنَا هِشَامٌ يَعْنِي ابْنَ سَعْدٍ عَنْ نَافِعٍ عَنْ ابْنِ عُمَرَ