Sahih Al Bukhari Hadith Number 786

Narrated Mutarrif bin `Abdullah: `Imran bin Husain and I offered the prayer behind `Ali bin Abi Talib. When `Ali prostrated, he said the Takbir, when he raised his head, he said the Takbir and when he got up for the third rak`a he said the Takbir. On completion of the prayer `Imran took my hand and said, “This (i.e. `Ali) made me remember the prayer of Muhammad” Or he said, “He led us in a prayer like that of Muhammad.”

10  Call to Prayers (Adhaan)
Hadith number 786
Volume no 1
Chapter: 116 ( Itmam At-Takbir (i.e., to end the number of Takbir, or to say the Takbir perfectly) on prostrating. [See Fath Al-Bari]