It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that one night we were on a journey with the Prophet (peace and blessings of Allah be upon him). We said: O Messenger of Allah (peace be upon him)! If you permit us, we will lie down on the ground and sleep, and our mounts can graze. The Prophet (peace be upon him) permitted and said, "One of you should keep watch." I offered myself, but I too fell asleep, and my eyes opened when the sun had already risen. The Prophet (peace be upon him) woke up upon hearing our voices. He ordered Sayyiduna Bilal (may Allah be pleased with him), so he gave the call to prayer (adhan) and the iqamah, and the Prophet (peace be upon him) led us in prayer.