صَحِيحُ مُسْلِمٍ
Sahih Muslim 54 b
The Book of Faith
Clarifying that no one will enter paradise but the believers; loving the believers is part of faith and spreading Salam is a means of attaining that
وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، أَنْبَأَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، بِهَذَا الإِسْنَادِ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَالَّذِي نَفْسِي بِيَدِهِ لاَ تَدْخُلُونَ الْجَنَّةَ حَتَّى تُؤْمِنُوا . بِمِثْلِ حَدِيثِ أَبِي مُعَاوِيَةَ وَوَكِيعٍ .
Zuhair b. Harb said: Jarir reported on the authority of A'mash with this chain of transmitters that the Messenger of Allah (ﷺ) 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'.
Sahih Muslim, 54 bSahihصحيح