Proverbs 14:33 (NKJV) — 33 Wisdom rests in the heart of him who has understanding, But what is in the heart of fools is made known.
Retaining wisdom, revealing folly. People of understanding will not tell all they know; they allow some things to rest in their hearts. Fools, on the other hand, find it quite impossible to hide the thoughts of their hearts. They will at some point be made public.