Musnad Ahmad 26:187

Abu Kamil narrated to us, Zuhayr narrated to us, Yahya al-Jabir Abu al-Harith al-Taymi narrated to us, that Abu Majid, a man from Banu Hanifa, narrated to him, saying: Abdullah ibn Mas’ud said: We asked our Prophet, peace and blessings of Allah be upon him, about walking with the funeral procession. He said: "The walking is at a pace less than a trot. If it is good, you are hastening it toward it—or he said: you are hastening it toward it—and if it is other than that, then away with the people of the Fire. The funeral procession is followed, and it does not follow; there is no part of it for one who precedes it."