اَ تَحْقِرَنَّ مِنَ الْمَعْرُوفِ شَيْئًا وَلَوْ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طَلْقٍ
The Prophet, peace and blessings be upon him, said, “Do not belittle any good deed, even meeting your brother with a cheerful face.” (Muslim)