مسند امام احمد بن حنبل · Hadith 5034

It was narrated that al-Hakam said: I saw Tawoos, when he started to pray, he would raise his hands, (and he would do the same) when he bowed and when he lifted his head from bowing. one of his companions told me that he narrated that from Ibn Umar, from the Prophet (PBUH).