Musnad Ahmad 26:38

Sufyan narrated to us, he said: And there is none among them who puts it forward. And it was read to Sufyan: I heard Yahya al-Jabir, from Abu Majid al-Hanafi, who said: I heard Abdullah say: We asked the Messenger of Allah, peace and blessings of Allah be upon him, about walking with the funeral procession, and he said: "It is followed, and it does not follow."