Chapter: Standing of the Prophet (pbuh) at night
Narrated Al-Mughira:The Prophet (ﷺ) used to stand (in the prayer) or pray till both his feet or legs swelled. He was asked why (he offered such an unbearable prayer) and he said, "should I not be a thankful slave."
Reference
Sahih al-Bukhari 1130
In-book reference
Book 19, Hadith 10
USC-MSA web (English)
Vol. 2, Book 21, Hadith 230
Translation by Dr. M. Muhsin Khan · Language: EN
Sahih
Arabic Text
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا مِسْعَرٌ، عَنْ زِيَادٍ، قَالَ سَمِعْتُ الْمُغِيرَةَ ـ رضى الله عنه ـ يَقُولُ إِنْ كَانَ النَّبِيُّ صلى الله عليه وسلم لَيَقُومُ لِيُصَلِّيَ حَتَّى تَرِمُ قَدَمَاهُ أَوْ سَاقَاهُ، فَيُقَالُ لَهُ فَيَقُولُ " أَفَلاَ أَكُونُ عَبْدًا شَكُورًا ".