Sahih Bukhari: Hadith 723

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 hamidah", and he used to do the same on rising from the second rak`a (for the 3rd rak`a). Ibn `Umar said: "The Prophet (ﷺ) used to do the same."