Musnad Ahmad 30:783

Yazid narrated to us, Muhammad—meaning Ibn ‘Amr—informed us, from ‘Abd al-Malik ibn al-Mughirah ibn Nawfal, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Every prayer in which the Mother of the Qur’an (Al-Fatihah) is not recited, it is deficient, it is deficient."