Rashi comments based on Avodah Zarah 45 that from this verse we learn that when one destroys an idol, its "roots" must be removed after it. A question can be asked, what are the "roots" of idol worship?

A fundamental principle in Judaism is the concept of Emunah (faith). This means that a person must feel totally and utterly dependent upon Hashems mercy.Everything is from G-d Almighty, nothing exits without Hashem willing it to be so.......Therefore, the roots of idol worship is basically the false notion that G-d is somewhat absent from the world,and that whatever happens is a coincidence, or attributed to any other force other than G-d. Its not enough to just physically destroy idols, but the "roots" of idol worship inherent in all of us must be eradicated as well.Let us all acknowledge G-ds existance by simply reinforcing our faith in G-ds dominion over the universe...Have a good Shabbos