Musnad Abu Ya'la al-Mawsili 106:5

Zakariya ibn Yahya al-Wasiti narrated to us, Hushaym narrated to us, from Yazid ibn Abi Ziyad, from Abd al-Rahman ibn Abi Layla, from al-Bara’ ibn Azib, who said: I saw the Messenger of Allah, may Allah bless him and grant him peace, when he began the prayer, he raised his hands until they were level with his thumbs or they were level with his ears.