Do not belittle any good
لَا تَحْقِرَنَّ مِنَ الْمَعْرُوفِ شَيْئًا، وَلَوْ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طَلْقٍ
La tahqiranna mina-l-ma'rufi shay'an, wa law an talqa akhaka bi-wajhin talq.
"Do not belittle any good deed, even meeting your brother with a cheerful face."
Narrated by Abu Dharr. Sahih Muslim 2626
A short reflection
A smile, a small act of welcome. Counted as ma'ruf. Multiplied by ten. The bar for sadaqah is lower than we think.