Yahya related to me from Malik from Yahya ibn Said from an-Numan
ibn Murra that the Messenger of Allah, may Allah bless him and grant
him peace, said,"What about drunkenness, stealing and adultery? "That
was before anything had been revealed about them. They said, "Allah
and His Messenger know best." He said, "They are excesses and in them
is a punishment. And the worst of thieves is the one who steals his
prayer." They said, "How does he steal his prayer, Messenger of
Allah?" He replied, "He does not do ruku or sajda properly."
Muwatta Malik Book 9, Hadith 80