It is narrated from Sayyiduna Abu Juhayfah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) was on that journey of his in which the Companions slept until the sun rose, and he (peace and blessings be upon him) said: "You were dead (that is, in sleep), and Allah returned your souls to you. Whoever sleeps through a prayer, let him pray it when he wakes up; and whoever forgets a prayer, let him pray it when he remembers it."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18488