كتاب السهو
Read the English translation first, with the original Arabic directly underneath.
Malik bin Numair Al-Khuza'I, one of the inhabitants of Al-Basrah, narrated that:
His father told him that he saw the Messenger of Allah (ﷺ) sitting when praying, putting his right forearm on his right thigh and raising his forefinger, which he had bent slightly, and he was supplicating.
أَخْبَرَنِي أَحْمَدُ بْنُ يَحْيَى الصُّوفِيُّ، قَالَ حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا عِصَامُ بْنُ قُدَامَةَ الْجَدَلِيُّ، قَالَ حَدَّثَنِي مَالِكُ بْنُ نُمَيْرٍ الْخُزَاعِيُّ، مِنْ أَهْلِ الْبَصْرَةِ أَنَّ أَبَاهُ، حَدَّثَهُ أَنَّهُ، رَأَى رَسُولَ اللَّهِ صلى الله عليه وسلم قَاعِدًا فِي الصَّلاَةِ وَاضِعًا ذِرَاعَهُ الْيُمْنَى عَلَى فَخِذِهِ الْيُمْنَى رَافِعًا أُصْبُعَهُ السَّبَّابَةَ قَدْ أَحْنَاهَا شَيْئًا وَهُوَ يَدْعُو .