Ṣaḥīḥ Muslim Ḥadīth [2626] – Meet Your Brother With a Cheerful Face…

حَدَّثَنِي أَبُو غَسَّانَ الْمِسْمَعِيُّ، حَدَّثَنَا عُثْمَانُ بْنُ عُمَرَ، حَدَّثَنَا أَبُو عَامِرٍ – يَعْنِي الْخَزَّازَ – عَنْ أَبِي عِمْرَانَ الْجَوْنِيِّ، عَنْ عَبْدِ اللَّهِ بْنِ الصَّامِتِ، عَنْ أَبِي ذَرٍّ، قَالَ: قَالَ لِيَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: لَا تَحْقِرَنَّ مِنَ الْمَعْرُوفِ شَيْئًا، وَلَوْ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طَلْقٍ 

Book [45]: The book of virtue, enjoining good manners, and joining of the ties of kinship
Chapter [43]: It is recommend to show a cheerful countenance when meeting others

Ḥadīth [2626]: It is narrated on the authority of Abī Dharr (may Allāh be pleased with him) that he said: Allāh’s Prophet (peace and blessings of Allāh be upon him) said to me: “Don’t consider anything insignificant out of good things even if it is that you meet your brother with a cheerful countenance.”