Prayer (Kitab Al-Salat): Details of Commencing Prayer

Dawud :: Book 3 : Hadith 854

Narrated AbuMas'ud al-Badri:

The Prophet (peace_be_upon_him) said: A man's prayer does not avail him unless he keeps his back steady when bowing and prostrating.

Source materials are from the University of Southern California MSA site
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