Musnad Ahmad 788:175

'Affan narrated to us, Abu 'Awanah narrated to us, Dawud ibn 'Abdullah al-Awdi narrated to us, from Humayd ibn 'Abd al-Rahman al-Himyari, that a man who was called Hummah, one of the companions of Muhammad, may Allah bless him and grant him peace, went out to Isfahan as a warrior during the caliphate of 'Umar, may Allah be pleased with him. He said: "O Allah, Hummah claims that he loves meeting You. If Hummah is truthful, then decree for him according to his truthfulness; and if he is a liar, then decree against him, even if he dislikes it. O Allah, do not return Hummah from this journey of his." He said: Then death took him—and 'Affan said once: "the stomach [ailment]"—so he died in Isfahan. He said: Then Abu Musa stood up and said: "O people, by Allah, we have not heard in what we heard from your Prophet, may Allah bless him and grant him peace, and our knowledge has not reached anything except that Hummah is a martyr."