and that ‘Alī killed al-Walīd and Hamza killed his opponent, although there is uncertainty as to whether Hamza’s opponent was ‘Utba or Shayba.

This principle should be understood, for it is useful in establishing the certainty of many transmitted accounts concerning hadith, Quranic commentary, the Prophet’s military campaigns, people’s words and deeds, and other matters. Thus, when a hadith to which this principle applies is transmitted from the Prophet, may Allah bless him and grant him peace, through two channels, and it is known that one did not derive it from the other, its truth can be established with certainty. This is especially so when its transmitters are known not to lie deliberately, and the only concern is that one of them might forget or make a mistake.

Anyone familiar with the Companions—such as Ibn Mas‘ūd, Ubayy ibn Ka‘b, Ibn ‘Umar, Jābir, Abū Sa‘īd, Abū Hurayra, and others—knows with certainty that none of them would deliberately lie about the Messenger of Allah, may Allah bless him and grant him peace, let alone those superior to them. This is just as a man knows, through long, close acquaintance with someone whose character he has tested, that he is not the sort to steal people’s property, commit highway robbery, bear false witness, or do similar things.

The same applies to the Successors in Medina, Mecca, Syria, and Basra. Anyone familiar with the likes of Abū Sālih al-Sammān, al-A‘raj, Sulaymān ibn Yasār, Zayd ibn Aslam, and their peers knows with certainty that they were not people who would deliberately lie in transmitting hadith