Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 737
Narated By AbuHurayrah : When the Apostle of Allah (pbuh) uttered the takbir (Allah is most great) for prayer (in the beginning), he raised his hands opposite to his shoulders; and when he bowed, he did like that; and when he raised his head to prostrate, he did like that; and when he got up at the end of two rak'ahs, he did like that.