Sahih Muslim Book 4, Hadith Number 1382.

Chapter : Forbiddance to go out of the mosque after the Adhan has been announced by the Mu’adhdhin.

Anas b. Sirin reported: I heard Jundab b. Qasri saying that the Messenger of Allah (may peace be upon him) said: He who observed the morning prayer (in congregation), he is in fact under the protection of Allah and it never happens that Allah should make a demand in connection with the protection (that He guarantees and should not get it) for when he asks for anything in relation to His protection, he definitely secures it. He then throws him flatly in the Hell-fire.