Musnad Ahmad 1018:3

Abdullah ibn Numayr narrated to us, al-A’mash narrated to us, from Abdullah ibn Yasar al-Juhani, from Abd al-Rahman ibn Abi Layla, who said: The companions of the Messenger of Allah (peace and blessings of Allah be upon him) narrated to us that they were traveling with the Messenger of Allah (peace and blessings of Allah be upon him) on a journey. A man among them slept, so some of them went to some arrows he had with him and took them. When the man woke up, he was frightened, and the people laughed. He said, "What makes you laugh?" They said, "Nothing, except that we took this man's arrows, and he became frightened." The Messenger of Allah (peace and blessings of Allah be upon him) said, "It is not lawful for a Muslim to frighten a Muslim."