THE BLIGHT OF SIN
Blight is a destructive plant disease that can infect any plant, even trees. Infected trees exhibit a blackening of the blooms, leaves and twigs, and the whole tree is eventually involved. The blight causes the tree to decay outwardly and the decay can eat all the way to the heart of then tree if left unchecked. This decay of the heart of the tree can eventually cause the death and destruction of the tree. When the disease gets to this point all it takes is a slight resistance against the tree, and it is toppled.
Just like the blight that infects the tree, sin can start eating away at a person. If left unchecked, it can cause spiritual and moral decay and eat to the very heart of a person.
(From a sermon by Mike Woodham, "Time for a New Commitment" 1/26/2009)