Hadith 390 - Prayers (Salat) - Sahih Al-Bukhari - صحيح البخاري - Collection of Actions, Sayings and Teachings of Prophet Muhammad (صلى الله عليه و سلم) - Kutub as-Sittah

8. Prayers (Salat) - كتاب الصلاة

27) Chapter: During Prostrations one should show his armpits and separate his forearms from his body

Narrated 'Abdullah bin Malik:

Ibn Buhaina, "When the Prophet (ﷺ) prayed, he used to separate his arms from his body so widely that the whiteness of his armpits was visible."

Reference: 390
English reference: Vol. 1, Book 8, Hadith 385
In-book reference: Book 8, Hadith 42
Grade: Sahih
Read this hadith from Darussalam Collection

27) باب يُبْدِي ضَبْعَيْهِ وَيُجَافِي فِي السُّجُودِ

أَخْبَرَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا بَكْرُ بْنُ مُضَرَ، عَنْ جَعْفَرٍ، عَنِ ابْنِ هُرْمُزَ، عَنْ عَبْدِ اللَّهِ بْنِ مَالِكٍ ابْنِ بُحَيْنَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ إِذَا صَلَّى فَرَّجَ بَيْنَ يَدَيْهِ حَتَّى يَبْدُوَ بَيَاضُ إِبْطَيْهِ‏.‏ وَقَالَ اللَّيْثُ حَدَّثَنِي جَعْفَرُ بْنُ رَبِيعَةَ نَحْوَهُ‏.‏