Musnad Abu Ya'la al-Mawsili 6:81

Mus'ab ibn 'Abd Allah al-Zubayri narrated to us, 'Abd al-'Aziz narrated to us, from Suhayl, from Ibn 'A'idh, from 'Amir ibn Sa'd, from his father Sa'd, who said: A man came while the Prophet, peace and blessings of Allah be upon him, was leading us in prayer, and he said: "O Allah, grant me the best of what You grant Your righteous servants." When the Messenger of Allah, peace and blessings of Allah be upon him, finished, he said: "Who was the speaker just now?" The man said: "I was." He said: "Then your horse will be hamstrung, and you will be killed in the way of Allah."