عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَالَّذِي نَفْسِي بِيَدِهِ لَا تَدْخُلُوا الْجَنَّةَ حَتَّى تُؤْمِنُوا وَلَا تُؤْمِنُوا حَتَّى تَحَابُّوا ثُمَّ قَالَ هَلْ أَدُلُّكُمْ عَلَى شَيْءٍ إِذَا فَعَلْتُمُوهُ تَحَابَبْتُمْ أَفْشُوا السَّلَامَ بَيْنَكُمْ
Syedna Abu Hurairah (may Allah be pleased with him) narrates that the Noble Prophet (peace and blessings be upon him) said: By Him in Whose hand is my soul! You will not enter Paradise until you have faith, and you will not have faith until you love one another. Shall I not tell you something which, if you do it, you will love one another? Spread the greeting of peace among yourselves.