“caused by their own lips.” The Hebrew uses the genitive, “trouble of their own lips,” and it is a genitive of origin, indicating the origin, source, or agent, and thus the verse is saying that the trouble “of” their lips is the trouble caused by their lips. The enemies were stirring up trouble by what they were saying. It is a consistent theme through Scripture that evil people bring evil upon themselves (see commentary on Prov. 1:18). Here the afflicted psalmist prays that what God so often said about the wicked being caught in their own wickedness will happen to his enemy.