When I was in high school, one of the guys filled a jar with shelled corn, poured in some water, sealed the lid, and tucked it away in his locker. We figured it had something to do with a science fair project. Whatever the reason, it sat there fermenting for weeks, and nobody paid it much attention until the day it tipped out, hit the floor, and exploded across the hallway. Out-stinking a high school locker room is no small feat, but that jar pulled it off. The smell of rotten fermentation soaked into everything, and it lingered for what felt like ages no matter how hard anyone scrubbed.

I’ve come to believe that bitterness works almost exactly like that jar. It begins unnoticeably, sealed up and out of sight. Given enough time in the dark, it ferments, and when it finally breaks open, the damage is far worse than anyone expected, and it clings to everything it touches.

Hurt is the one experience none of us escapes. It might arrive through a person who wounds us, or through a circumstance that blindsides us, but it comes to all of us sooner or later. The hurt itself isn’t the deciding factor in how our lives turn out. What we do with the hurt is what makes all the difference.

Years ago my wife came home from a party with a small bottle of concentrated cinnamon oil. Someone had told her about an experiment, and she asked if she could try it on me. I laughed and let her rub a drop on the bottom of my foot. Within ten or twelve minutes, the taste buds on my tongue were popping with the flavor of cinnamon. The oil had traveled from the sole of my foot, through the skin, into the bloodstream, and up to my mouth. I had not swallowed a thing. The chemistry of my body did all the work without my permission.

That little kitchen experiment is harmless and a bit funny. The principle behind it is not. Whatever touches the skin can be carried to the heart. If a five-gallon bucket of Agent Orange were sitting at the front of the room and someone invited a line of people to come up and dip their hands in it, no one would step forward. We understand that some things, once absorbed, do not stay where they were applied. They travel. They contaminate. They kill slowly and from the inside.

There is a poison like that for the soul, and the author of Hebrews names it directly.

“Strive for peace with everyone, and for the holiness without which no one will see the Lord. See to it that no one fails to obtain the grace of God; that no ‘root of bitterness’ springs up and causes trouble, and by it many become defiled.” (Hebrews 12:14–15)

Bitterness is the poison that no one volunteers to drink, and that almost everyone ends up absorbing through the skin of an unresolved wound.