Musnad Ahmad 498:3

Harun ibn Ma'ruf narrated to us, Ibn Wahb narrated to us, Al-Layth ibn Sa'd informed me, from 'Abd Rabbih ibn Sa'id, from 'Imran, from 'Abdullah, from Rabi'ah ibn al-Harith, from al-Fadl ibn 'Abbas, from the Messenger of Allah (peace and blessings of Allah be upon him), who said: "The prayer is two by two; you recite the Tashahhud in every two rak'ahs, and you show humility, and you show submissiveness, and you show stillness. Then you raise your hands—he said: you lift them—to your Lord, facing your face with their palms, and you say: 'O Lord, O Lord'—three times. Whoever does not do that, it is deficient." Abu 'Abd al-Rahman said: "This, in my view, is the correct version."