When weeding, we need to pull out the roots or the weeds will grow back.
Eradicating bad habits is the same. Remove the root, or the habit will reappear. A person unskilled at weeding will often begin by removing the stems and the leaves - that which lies above the soil. But seemingly overnight, the weeds start growing back. And so the novice gardener learns a valuable lesson. Removing just the visible parts of the plant will not eliminate it.
The roots need to be located, uncovered, and dug out. In a similar manner, we often try to shed bad habits just by curtailing visible behaviors. But this fails to remove underlying causes. Not surprisingly, as soon as we relax our guard, the bad habits return. As rampant as those weeds.
To permanently eradicate bad habits, we need to destroy their roots. How? First we need to determine the habit's underlying causes - maybe selfishness, maybe apathy, or a lack of integrity. By figuring out our bad habit's causes we can eliminate them forever.
— Our Daily Practice, Venerable Wuling