Sahih Bukhari
Characteristics of Prayer
Volume: 001 / Book Number: 012 / Hadith Number: 706
Narrated Nafi':
Whenever Ibn 'Umar started the prayer with Takbir, he used to raise his hands: whenever he bowed, he used to raise his hands (before bowing) and also used to raise his hands on saying, "Sami a-l-lahu Liman hamida", and he used to do the same on rising from the second Rak'a (for the 3rd Rak'a). Ibn 'Umar said: "The Prophet used to do the same."