Maliks Muwatta Book 010, Hadith Number 009.

Section : The Takbir and the Recitation in the Prayer of the Two Ids.

Yahya related to me from Malik that Nafi, the mawla of Abdullah ibn Umar said, "I was at Adha and Fitr with Abu Hurayra and he said 'Allah is greater' seven times in the first raka, before the recitation, and five times in the second, before the recitation."