Mahmud b. al-Rabi', on whose face the Messenger of Allah ( صلی اللہ علیہ وسلم ) squirted water from the well, reported on the authority of 'Ubada b. as- Samit that the Messenger of Allah ( صلی اللہ علیہ وسلم ) said:
He who does not recite Umm al-Qur'an is not credited with having observed prayer.