It is narrated from Sayyiduna Mu'adh bin Anas al-Juhani (may Allah be pleased with him); he said: I took part with the Messenger of Allah (peace and blessings be upon him) in such-and-such a campaign. The people crowded the camping places and blocked the road, so the Messenger of Allah (peace and blessings be upon him) sent a crier, who announced among the people: "Whoever crowds a camping place or blocks a road, his jihad is not accepted."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17569