Your smile is a charity
تَبَسُّمُكَ فِي وَجْهِ أَخِيكَ لَكَ صَدَقَةٌ
Tabassumuka fi wajhi akhika laka sadaqah.
"Your smile to your brother is a charity from you."
Narrated by Abu Dharr. Sunan at-Tirmidhi 1956
A short reflection
The lowest unit of sadaqah. No money, no time, no possession required. A reflex of the face, counted as gold.