Musnad Ahmad 833:9

'Affan narrated to us, Hammam narrated to us, Qatadah narrated to us, from Nasr ibn 'Asim, from Malik ibn al-Huwayrith: "That the Prophet, peace and blessings of Allah be upon him, used to raise his hands level with the lobes of his ears during bowing (ruku') and prostration (sujud)."