Musnad Ahmad 30:2776

Muhammad ibn Ja'far narrated to us, he said: Shu'bah narrated to us, from 'Abd al-Malik ibn 'Umayr, he said: I heard Salim al-Barrad, Abu 'Abd Allah, say: I heard Abu Hurayrah say: I heard the Prophet, peace and blessings of Allah be upon him, say: "Whoever follows a funeral procession and prays over it—or he said: whoever prays over it (Shu'bah was in doubt)—then for him is a qirat. And if he witnesses its burial, then for him are two qirats. The qirat is like Uhud."