Musnad Abu Ya'la al-Mawsili 154:40

Muhammad ibn Abdullah ibn Numayr narrated to us, Ibn Fudayl narrated to us, from Asim ibn Kulayb, from Muharib ibn Dithar, from Ibn Umar, that he used to raise his hands whenever he bowed and whenever he rose. I said, "What is this?" He said, "The Messenger of Allah (ﷺ), when he stood up after the two rak'ahs, would say the takbir and raise his hands."