ENOfficial
Abu Dharr reported God’s messenger as saying, “Do not consider any act of kindness insignificant, even meeting your brother with a cheerful face.” Muslim transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي ذَرٍّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لَا تَحْقِرَنَّ مِنَ الْمَعْرُوفِ شَيْئًا وَلَوْ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طليق» . رَوَاهُ مُسلم
sunnah.com