Sahih Ibn Khuzaymah

Hazrat Saeed bin Sam'an narrates that Sayyiduna Abu Hurairah (may Allah be pleased with him) came to us in the mosque of Banu Zuraiq and said that there are three actions which the Messenger of Allah (peace and blessings be upon him) used to do, but people have abandoned them. When the Prophet (peace and blessings be upon him) would stand for prayer, he would do like this—Abu Amir demonstrated with his hand—and he neither kept much distance between his fingers nor joined them together (rather, he kept them in a moderate position), and said that Ibn Abi Dhi’b had shown us in this manner. Imam Abu Bakr (may Allah have mercy on him) says that (our teacher) Yahya bin Hakeem demonstrated to us by raising his hands and did not keep much distance between his fingers, nor did he join them together, and he raised both his hands up to above his head. And the Noble Prophet (peace and blessings be upon him) would stand silently for a short while before reciting and would ask Allah Almighty for His grace and bounty, and whenever he (peace and blessings be upon him) would prostrate in prayer and rise from prostration, he would say « اللهُ أَكْبَرُ ». Imam Abu Bakr (may Allah have mercy on him) says that this confusion is, in every case, a very severe confusion. I do not know to which narrator this belongs. However, in the words that he (peace and blessings be upon him) raised his hands well, there is no doubt that the one praying should raise his hands above his head at the beginning of the prayer.