Stone him to death: this is the action commanded (see 13.10).
Purge the evil from your midst: the effect of taking the action (see verse 9).
All Israel shall hear, and fear: the result (see 13.11).
Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .