Musannaf Ibn Abi Shaybah

Hazrat Mahmood bin Rabee’ says that I offered prayer with Hazrat Ubadah bin Samit. He recited Surah Al-Fatihah in the prayer. After the prayer, I submitted, “O Abu Al-Waleed! I heard you reciting Surah Al-Fatihah?” He said, “Yes, without it the prayer is not valid.”