Prayer (Kitab Al-Salat)

Dawud :: Book 2 : Hadith 618

Narrated Ali ibn AbuTalib:

The Prophet (peace_be_upon_him) said: The key of prayer is purification; takbir (saying "Allah is most great") makes (all acts which break prayer) unlawful and taslim (uttering the salutation) makes (all such acts) lawful.

Source materials are from the University of Southern California MSA site
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