The Messenger of Allah (ﷺ) said: I was commanded to prostrate myself on the seven (bones) and forbidden to fold back hair and clothing. (The seven bones are): forehead, nose, hands, knees and feet.
Why is it that you touched my head? He (Ibn 'Abbas) replied: (The man who observes prayer with plaited hair) is like one who prays with his hands tied behind.
حَدَّثَنَا عَمْرُو بْنُ سَوَّادٍ، أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، أَخْبَرَنَا عَمْرُو بْنُ الْحَارِثِ، وَاللَّيْثُ بْنُ سَعْدٍ، كِلاَهُمَا عَنْ جَعْفَرِ بْنِ رَبِيعَةَ، بِهَذَا الإِسْنَادِ . وَفِي رِوَايَةِ عَمْرِو بْنِ الْحَارِثِ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا سَجَدَ يُجَنِّحُ فِي سُجُودِهِ حَتَّى يُرَى وَضَحُ إِبْطَيْهِ . وَفِي رِوَايَةِ اللَّيْثِ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا سَجَدَ فَرَّجَ يَدَيْهِ عَنْ إِبْطَيْهِ حَتَّى إِنِّي لأَرَى بَيَاضَ إِبْطَيْهِ .
" When the Messenger of Allah (rtiay peace be upon him) prostrated, he spread out his arms so that the whiteness of his armpits was visible." And in the narration transmitted by al-Laith (the words are:" When the Messenger of Allah (ﷺ) prostrated. he spread his hands from the armpits so that I saw their whiteness."
حَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ الْحَنْظَلِيُّ، أَخْبَرَنَا مَرْوَانُ بْنُ مُعَاوِيَةَ الْفَزَارِيُّ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ الأَصَمِّ، عَنْ يَزِيدَ بْنِ الأَصَمِّ، أَنَّهُ أَخْبَرَهُ عَنْ مَيْمُونَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا سَجَدَ خَوَّى بِيَدَيْهِ - يَعْنِي جَنَّحَ - حَتَّى يُرَى وَضَحُ إِبْطَيْهِ مِنْ وَرَائِهِ وَإِذَا قَعَدَ اطْمَأَنَّ عَلَى فَخِذِهِ الْيُسْرَى .
When the Messenger of Allah (ﷺ) prostrated himself, he spread his arms, i. e. he separated them so much that the whiteness of his armpits became visible from behind and when he sat (for Jalsa) he rested on his left thigh.