Bulugh al-Maram 318
Book 2 (The Book of Prayer), Hadith 139
The Book of Prayer
وَفِي لَفْظٍ لِأَحْمَدَ : { فَأَقِمْ صُلْبَكَ حَتَّى تَرْجِعَ اَلْعِظَامُ } 11 - صحيح . وهذه الرواية عند أحمد (4/340) ، وابن حبان (1787) وزادا : "إلى مفاصلها " .
And Ahmad has: "Keep your back straight till the bones return (to their positions)."
Type / for formatting · select text for toolbar
Saved to this device only