What is Allah’s warning to those who avoid spending wealth in His cause?

1. Those who are tight-fisted with the bounty Allah has given them should not suppose that that is better for them. No indeed, it is worse for them! What they were tight-fisted with will be hung around their necks on the Day of Rising. Allah is the inheritor of the heavens and the earth and Allah is aware of what you do.
(3:180)

2. As for those who are tight-fisted and direct others to be tight-fisted, and hide the bounty Allah has given them, We have prepared a humiliating punishment for those who disbelieve.
(4:37)