Who are the “wise” (in God)?
Only those “who understand (Scripture)”.

Proof verse?

“Many will be purified, made spotless and refined, but the wicked will continue to be wicked. None of the wicked will understand, but those who are wise will understand.” (Daniel 12:10)

P/S:

The more one “understands Scripture”, it could imply that the “wiser such a one is in the Lord” (highly suggestive by the verse above) by His Will in His Mercy.