Bitterness is an acid that destroys its own container. (Adrian Rogers, radio preacher)
It frightening to know that the gastric acids in our stomachs can eat through wood and small pieces of metal. It’s comforting to know, however, that those acids destroy bacteria and viruses that could do our bodies harm. Also, our stomachs have a protective lining that keeps the acid from burning through and harming us. If bitterness is like an acid, think of what harm it can do.
Watch out that no poisonous root of bitterness grows up to trouble you, corrupting many. (Hebrews 12:15)