John Gill Commentary James 5:2

"Your riches are corrupted, and your garments are moth-eaten." — James 5:2 (ASV)

Your riches are corrupted
Either through disuse of them; and so the phrase is expressive of their tenaciousness, withholding from themselves and others what is proper, and which is keeping riches for the owners of them, to their hurt; or these are corrupted, and are corruptible things, fading and perishing, and will be of no use in the day of wrath, and therefore it is great weakness to put any trust and confidence in them.

and your garments are moth eaten
being neither worn by themselves, nor put upon the backs of others, as they should, but laid up in wardrobes, or in chests and coffers, and so became food for moths, and now good for nothing.