People like that, who almost universally profess Christian faith, should be attentive to the words of the early Church fathers on the intrinsically corrupting nature of wealth:

"The rich are in possession of the goods of the poor, even if they have acquired them honestly or inherited them legally."
— John Chrysostom

"You are not making a gift of your possession to the poor person. You are handing over to him what is his."
— Ambrose of Milan

"The property of the wealthy holds them in chains [...] which shackle their courage and choke their faith and hamper their judgment and throttle their souls. They think of themselves as owners, whereas it is they rather who are owned: enslaved as they are to their own property, they are not the masters of their money but its slaves."
—Cyprian

And for a direct Bible passage, it's hard to be more succinct than James.

I'll need to take your word for it.