Tafsir of At-Tawbah 9:78

{Their secrets and their private conversations} That which they conceal of hypocrisy and their resolve to break what they promised, and what they whisper to one another regarding slanders against the religion, labeling charity as a tribute (jizya), and plotting to withhold it.

{Those who criticize the contributors among the believers concerning [their] charities and [those who] find nothing [to give] except their effort, so they mock them—Allah will mock them, and for them is a painful punishment.}