Sahih Bukhari | Volume 1 | Hadith Number 706

Narrated by 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."