Ibn Abu Laila said he was told by Muhammad’s companions that during a journey with Allah's Messenger ﷺ while one of them was asleep another went to a rope he had with him and seized him,* with the result that he was startled. Allah's Messenger ﷺ then said, “It is not lawful for a Muslim to frighten another.” Abu Dawud transmitted it. * The meaning is that he tied the rope round him while he was asleep, presumably as a joke.