It is narrated from Sayyiduna Ali (may Allah be pleased with him), he says: I was a person who used to sleep a lot, so when I would offer Maghrib and my clothes were on me, I would fall asleep. Then once Yahya bin Saeed, while quoting Ali (may Allah be pleased with him), said: So I used to sleep before Isha. When I asked the Messenger of Allah (peace and blessings be upon him) about this, he (peace and blessings be upon him) granted me permission.