Sahih Muslim Book 1, Hadith Number 97.

Chapter : Concerning the fact that no one will enter Paradise except believers, that love for believers is (a characteristic (feature of) Faith and giving currency to (the practice of paying salutation by, saying) As-Salimu ‘Alaikum (peace be upon you) is the means to achieve it (Faith).

Zuhair b. Harb said: Jarir reported on the authority of A’mash with this chain of transmitters that the Messenger of Allah (may peace be upon him) observed: By him in Whose hand is my life, you shall not enter Paradise unless you believe. The rest of the hadith is the same as narrated by Abd Mu’awiya and Waki’.