[Machine] The Messenger of Allah, ﷺ , used to spread his arms when he prayed until his armpits were visible. Abu Salih Al-Juhani said in his narration that the Messenger of Allah, ﷺ , when he prostrated, would move his arms away from his sides until the whiteness of his armpits could be seen.
أَنَّ رَسُولَ اللهِ ﷺ كَانَ إِذَا صَلَّى فَرَّجَ بَيْنَ يَدَيْهِ حَتَّى يَبْدُوَ إِبِطَاهُ وَقَالَ أَبُو صَالِحٍ الْجُهَنِيُّ فِي حَدِيثِهِ كَانَ رَسُولُ اللهِ ﷺ إِذَا سَجَدَ جَافَى عَضُدَيْهِ عَنْ جَنْبَيْهِ حَتَّى يُرَى بَيَاضُ إِبِطَيْهِ