Hazrat Abdullah bin Mas'ud (may Allah be pleased with him) narrates that we were returning from Hudaybiyyah with the Noble Prophet (peace and blessings be upon him). The companions state that they stopped at a sand dune. Ibn Mas'ud says, the Messenger of Allah (peace and blessings be upon him) said: "Who will guard us?" The narrator says that Hazrat Bilal said: "I will!" So the Noble Prophet (peace and blessings be upon him) said: "Then we will sleep." The narrator says that everyone slept until the sun rose. The narrator says: a few people woke up, among them so-and-so and so-and-so, and among them was Umar bin Khattab as well. They say that then we said: "Talk amongst yourselves." The narrator says that then the Noble Prophet (peace and blessings be upon him) also woke up and he said: "Do as you were doing." The narrator says that then we did (i.e., we prayed). The narrator says that the Prophet (peace and blessings be upon him) said: "Whoever forgets a prayer or sleeps through it, let him do as you have done."