Fish farmers in the southern U.S. had a small problem. Algae was filling their ponds, so they took the seemingly innocent step of importing Asian carp—which can grow to 100 pounds and eat 40 percent of their body weight each day—to clean the bottom of their ponds. But flooding swept the carp into the Mississippi River, which they navigated until they entered the Chicago Sanitary and Ship Canal, a mere 40 miles from Lake Michigan.

Now the entire region has a large problem, for if the Asian carp reach Lake Michigan, their insatiable appetite for plankton may upset the food chain and disrupt the Great Lakes’ $7 billion-per-year fishing industry.

Little acts can have large consequences. King Saul lost his kingdom for two small sins. His first mistake was not waiting for Samuel to arrive to offer sacrifices. But who can blame him? Samuel was late (from Saul’s perspective) and Saul’s army was slipping away. If Saul didn’t seek the Lord’s favor soon, he would go to war without God’s blessing (1 Samuel 13:5-9).

Saul’s second failure came on the heels of a signature victory. His armies defeated the Amalekites; but rather than destroy everything as God had commanded, Saul and his men “kept the best of the sheep and goats, the cattle, the fat calves, and the lambs—everything, in fact, that appealed to them” (1 Samuel 15:9).

The root of these seemingly insignificant sins was the sin of fear. Saul feared losing his army, either by not offering the sacrifice fast enough or by sacrificing something his men wanted. But he feared his men more than he feared God, and God responded by revoking his kingship.

Learn the lesson of Saul: some sins are understandable, but none are excusable—and all are devastating.