صحيح مسلم

Abu Burda reported on the authority of his father: We offered the sunset prayer along with Allah's Messenger (ﷺ). We then said: If we sit (along with Allah's Messenger) and observe night prayer with him it would be very good, so we sat down and he came to us and said: You are still sitting here. I said: Allah's Messenger, we observed evening prayer with you, then we said: Let us sit down and observe night prayer along with you, whereupon he said: You have done well or you have done right. He then lifted his head towards the sky and it often happened that as he lifted his head towards the sky, he said: The stars are a source of security for the sky and when the stars disappear there comes to the sky, i. e. (it meets the same fate) as it has been promised (it would plunge into darkness). And I am a source of safety and security to my Companions and when I would go away there would fall to the lot (of my Companions) as they have been promised with and my Companions are a source of security for the Umma and as they would go there would fall to the lot of my Umma as (its people) have been promised.