Sincerity

O believers, do not ruin your charity with reminders or hurtful words, like one who spends only to be seen by people and does not truly believe in Allah and the Last Day. His example is like a rock covered with dust; when rain falls, it washes it away, leaving nothing behind.

2:264O ye who believe! Render not vain your almsgiving by reproach and injury, like him who spendeth his wealth only to be seen of men and believeth not in Allah and the Last Day. His likeness is as the likeness of a rock whereon is dust of earth; a rainstorm smiteth it, leaving it smooth and bare. They have no control of aught of that which they have gained. Allah guideth not the disbelieving folk.