رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 378
The Book of Miscellany
Excellence and Etiquette of Sincere love for the sake of Allah
وَعَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : وَالَّذِي نَفْسِي بِيَدِهِ لاَ تَدْخُلُوا الْجَنَّةَ حَتَّى تُؤْمِنُوا وَلاَ تُؤْمِنُوا حَتَّى تَحَابُّوا أَوَلاَ أَدُلُّكُمْ عَلَى شيء إِذَا فَعَلْتُمُوهُ تَحَابَبْتُمْ: أَفْشُوا السَّلاَمَ بَيْنَكُمْ (( رَوَاهُ مُسْلِم)) .
Abu Hurairah (May Allah be pleased with him) reported: Messenger of Allah (ﷺ) said, "By Him in Whose Hand my soul is! You will not enter Jannah until you believe, and you shall not believe until you love one another. May I inform you of something, if you do, you love each other. Promote greeting amongst you (by saying As-salamu 'alaikum to one another)". [Muslim].
Riyad as-Salihin, 378