It is narrated from Sayyiduna Abu Tha'labah (may Allah be pleased with him); he said: The people's way was that whenever the Messenger of Allah (peace and blessings be upon him) halted at a place to camp, they would scatter in the mountain passes and valleys. So the Messenger of Allah (peace and blessings be upon him) stood up and said: "This is only the work of Satan." After that, whenever they halted at a place, they would gather close to one another, so much so that you would say that if a single cloak were spread over them, it would cover them all, or something to that effect.
Hadith Referenceالمعجم الكبير للطبراني / باب اللام ألف / 18806