Daraqutni

Salim (may Allah have mercy on him) narrates from his father, Sayyiduna Abdullah bin Umar (may Allah be pleased with them both): When the Prophet Muhammad (peace and blessings be upon him) would stand for prayer, he would raise both his hands until they were in line with his shoulders, then he would say the takbir. When he was about to go into bowing (ruku‘), he would raise both his hands until they were in line with his shoulders, then he would go into ruku‘. When he would rise from ruku‘, he would raise both his hands until they were in line with his shoulders, then he would recite “Sami‘ Allahu liman hamidah,” then proceed to prostration (sujud). Between the prostrations, he would not raise his hands. Throughout the entire prayer, whenever he would say the takbir while going into ruku‘, he would raise his hands.