(150) باب صَلاَةِ مَنْ لاَ يُقِيمُ صُلْبَهُ فِي الرُّكُوعِ وَالسُّجُودِ
Narrated AbuMas'ud al-Badri:
The Prophet (ﷺ) said: A man's prayer does not avail him unless he keeps his back steady when bowing and prostrating. (DE)
Reference (DE): Sunan Abi Dawud 855 (DE)
In-book reference (DE): Book 2, Hadith 465 (DE)
English translation (DE): Book 3, Hadith 854 (DE)