Sahih Muslim Book 4, Hadith Number 772.

Chapter : The reciting of Takbir at the time of bowing and rising in prayer except rising after Ruku’ when it is said: Allah listened to him who praised Him.

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.