Ubadah bin al-Samit reported the Messenger of Allah ﷺ as saying: the prayer is not valid I one does not recite fatihat al-kitab and something more, sufyan ( the narrator) said: This applies to a man who prays alone.

Narrated Ubadah ibn as-Samit: We were behind the Messenger of Allah ﷺ at the dawn prayer, and he recited (the passage), but the recitation became difficult for him. Then when he finished, he said: Perhaps you recite behind your imam? We replied: Yes, it is so, Messenger of Allah. He said: Do not do so except when it is Fatihat al-Kitab, for he who does not recite it is not credited with having prayed.

Narrated Abud Darda and Ubadah ibn as-Samit: Khalid ibn Dihqan said: When we were engaged in the battle of Constantinople at Dhuluqiyyah, a man of the people of Palestine, who was one of their nobility and elite and whose rank was known to them, came forward. He was called Hani ibn Kulthum ibn Sharik al-Kinani. He greeted Abdullah ibn Zakariyya who knew his rank. Khalid said to us: Abdullah ibn Abu Zakariyya told us: I heard Umm ad-Darda say: I heard Abud Darda say: I heard the Messenger of Allah ﷺ say: It is hoped that Allah may forgive every sin, except in the case of one who dies a polytheist, or one who purposely kills a believer. Hani ibn Kulthum ar-Rabi then said: I heard Mahmud ibn ar-Rabi transmitting a tradition from Ubadah ibn as-Samit who transmitted from the Messenger of Allah ﷺ who said: If a man kills a believer unjustly, Allah will not accept any action or duty of his, obligatory or supererogatory. Khalid then said to us: Ibn Abu Zakariyya transmitted a tradition to us from Umm ad-Darda on the authority of Abud Darda from the Messenger of Allah ﷺ who said: A believer will continue to go on quickly and well so long as he does not shed unlawful blood; when he sheds unlawful blood, he becomes slow and heavy-footed. A similar tradition has been transmitted by Hani ibn Kulthum from Mahmud ibn ar-Rabi on the authority of Ubadah ibn as-Samit from the Messenger of Allah ﷺ.