Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) was returning at night from Hudaybiyyah, and we camped on soft ground. The Prophet (peace and blessings be upon him) said: "Who will guard us?" Sayyiduna Bilal (may Allah be pleased with him) said: "I will." The Prophet (peace and blessings be upon him) said: "You will fall asleep." But he said: "No, I will not." However, he fell asleep, and Sayyiduna Umar (may Allah be pleased with him) along with so-and-so and so-and-so woke up first. Sayyiduna Umar (may Allah be pleased with him) said: "Talk, talk (so that the Messenger of Allah, peace and blessings be upon him, wakes up)." Then the Noble Prophet (peace and blessings be upon him) woke up and said: "Do as you do." So they did as they used to, and then the Prophet (peace and blessings be upon him) said: "Do likewise; this command is for the one among you who sleeps through the prayer or forgets it."