When the Prophet ﷺ prostrated, lie spread out his arms so that the whiteness of his armpits was visible.  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا صَلَّى فَرَّجَ بَيْنَ يَدَيْهِ حَتَّى يَبْدُوَ بَيَاضُ 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."  

عَنْ جَعْفَرِ بْنِ رَبِيعَةَ بِهَذَا الإِسْنَادِ وَفِي رِوَايَةِ عَمْرِو بْنِ الْحَارِثِ كَانَ رَسُولُ اللَّهِ ﷺ إِذَا سَجَدَ يُجَنِّحُ فِي سُجُودِهِ حَتَّى يُرَى وَضَحُ إِبْطَيْهِ وَفِي رِوَايَةِ اللَّيْثِ أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا سَجَدَ فَرَّجَ يَدَيْهِ عَنْ إِبْطَيْهِ حَتَّى إِنِّي لأَرَى بَيَاضَ إِبْطَيْهِ  

When the Messenger of Allah ﷺ prostrated himself, if a lamb wanted to pass between his arms, it could pass.  

كَانَ النَّبِيُّ ﷺ إِذَا سَجَدَ لَوْ شَاءَتْ بَهْمَةٌ أَنْ تَمُرَّ بَيْنَ يَدَيْهِ لَمَرَّتْ  

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.  

أَنَّهُ أَخْبَرَهُ عَنْ مَيْمُونَةَ زَوْجِ النَّبِيِّ ﷺ قَالَتْ كَانَ رَسُولُ اللَّهِ ﷺ 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, he kept his hands so much apart from each other that when it was seen from behind the armpits became visible. Waki' said: That is their whiteness.  

كَانَ رَسُولُ اللَّهِ ﷺ إِذَا سَجَدَ جَافَى حَتَّى يَرَى مَنْ خَلْفَهُ وَضَحَ إِبْطَيْهِ قَالَ وَكِيعٌ يَعْنِي بَيَاضَهُمَا  

The Messenger of Allah ﷺ used to begin prayer with takbir (saying Allahu Akbar) and the recitation: "Praise be to Allah, the Lord of the Universe." When he bowed he neither kept his head up nor bent it down, but kept it between these extremes; when he raised his head after bowing he did not prostrate himself till he had stood erect; when he raised his head after prostration he did not prostrate himself again till he sat up. At the end of every two rak'ahs he recited the tahiyya; and he used to place his left foot flat (on the ground) and raise up the right; he prohibited the devil's way of sitting on the heels, and he forbade people to spread out their arms like a wild beast. And he used to finish the prayer with the taslim.  

كَانَ رَسُولُ اللَّهِ ﷺ يَسْتَفْتِحُ الصَّلاَةَ بِالتَّكْبِيرِ وَالْقِرَاءَةَ بِ { الْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ} وَكَانَ إِذَا رَكَعَ لَمْ يُشْخِصْ رَأْسَهُ وَلَمْ يُصَوِّبْهُ وَلِكَنْ بَيْنَ ذَلِكَ وَكَانَ إِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ لَمْ يَسْجُدْ حَتَّى يَسْتَوِيَ قَائِمًا وَكَانَ إِذَا رَفَعَ رَأْسَهُ مِنَ السَّجْدَةِ لَمْ يَسْجُدْ حَتَّى يَسْتَوِيَ جَالِسًا وَكَانَ يَقُولُ فِي كُلِّ رَكْعَتَيْنِ التَّحِيَّةَ وَكَانَ يَفْرِشُ رِجْلَهُ الْيُسْرَى وَيَنْصِبُ رِجْلَهُ الْيُمْنَى وَكَانَ يَنْهَى عَنْ عُقْبَةِ الشَّيْطَانِ وَيَنْهَى أَنْ يَفْتَرِشَ الرَّجُلُ ذِرَاعَيْهِ افْتِرَاشَ السَّبُعِ وَكَانَ يَخْتِمُ الصَّلاَةَ بِالتَّسْلِيمِ وَفِي رِوَايَةِ ابْنِ نُمَيْرٍ عَنْ أَبِي خَالِدٍ وَكَانَ يَنْهَى عَنْ عَقِبِ الشَّيْطَانِ