Sayyiduna Abu Musa Ash’ari (may Allah be pleased with him) narrates: We performed the Maghrib prayer behind the Prophet (peace and blessings be upon him), so we said: If we wait until we also perform the ‘Isha prayer behind you (that would be appropriate), so we began to wait. The Prophet (peace and blessings be upon him) came to us and asked: Have you been here since that time? We replied: Yes, we wish to perform the ‘Isha prayer behind you. The Prophet (peace and blessings be upon him) said: You have done well (the narrator is unsure, perhaps these are the words:) You have done right. Then the Prophet (peace and blessings be upon him) raised his head towards the sky and said: The stars are the guardians (or protectors) of the sky. When these stars disappear, then that which you have been promised will come upon the sky. And I am the protector of my companions. When I depart, then that which has been promised to my companions will come upon them. And my companions are the protectors for my Ummah. When my companions depart, then that which has been promised to my Ummah will come upon them.

(Imam Ibn Hibban, may Allah have mercy on him, says:) There is a possibility that the meaning of this narration is that Allah Almighty has made the stars a sign for the preservation of the heavens and a means to prevent the sky from perishing. When these are destroyed and fade away, and perishing overtakes the sky, as has been decreed for it, in the same way Allah Almighty has made Sayyiduna Muhammad (peace and blessings be upon him) a means of protection for his companions from tribulations. When Allah Almighty takes him and brings him to His Paradise, then those tribulations will come to his companions which have been promised to them. Allah Almighty has made the companions of the Prophet (peace and blessings be upon him) protectors for his Ummah, who are a means of preventing the appearance of oppression and tyranny in the Ummah. When his companions depart, then that which has been promised to the Ummah will come to them, which will be related to the appearance of wrongful things, connected to oppression and falsehood.