Sahih Muslim 54
Sahih Muslim · Book 1: 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
Zuhair b. Harb said:
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 .
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'.