Saint Paisios the Athonite

Warped pieces of wood 

People who won’t accept a word of advice, even from people who love them, are, in the end, like warped pieces of wood and render themselves useless spiritually.

Just as planks that you can’t plane to make furniture end up as scaffolding or a staircase where they’re trodden on and muddied and eventually end up in the fire, these people are also destroyed, in the end.

Source:  pemptousia.com