The Book of Prayers (Kitab Al-Salat) 
Muslim :: Book 4 : Hadith 772
Ubada b. as-Samit reported: The Messenger of Allah (may peace be upon him) said: He who does not recite Umm al-Qur'an is not credited with having observed the prayer.
The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 772
Ubada b. as-Samit reported: The Messenger of Allah (may peace be upon him) said: He who does not recite Umm al-Qur'an is not credited with having observed the prayer.