An old parable told by a Haitian pastor makes the point.

A certain man wanted to sell his house for two thousand dollars. Another man wanted to buy it very badly, but he was a poor man and didn’t have the full price. After much bargaining, the owner agreed to sell the house to the man for one thousand dollars. But the reduced price came with a stipulation. The owner would sell the house, but he would keep ownership of a large nail protruding from over the front door.

Several years later, the original owner decided he wanted to buy the house back. Understandably, the new owner was unwilling to sell. As a result, the original owner went out, found the carcass of a dead dog in the street, and hung it from the nail he still owned. Soon the house became unlivable, and the family was forced to sell to the owner of the nail.

The Haitian pastor concluded the story:  "If we leave the Devil with even one small peg in our life, he will return to hang his rotting garbage on it, making it unfit for Christ's habitation."