What does Psalm 10:7 mean?

This posts three accusations against the wicked person (Psalm 10:2–6). His words exhibit profanity, lies, and abuse. The imagery of "mischief and iniquity" lurking under the person's tongue is striking. It suggests that whenever the person moves their tongue—whenever he speaks—deceit and evil are exposed.

The apostle Paul cites this verse in Romans 3:14 with a slight variation: "Their mouth is full of curses and bitterness." In Job 20, Zophar describes the wicked as having joy for only a moment (Job 20:5). He says evil is sweet in the mouth of the wicked. He "is loath to let it go and holds it in his mouth" (Job 20:13). However, Zohar states, "His food is turned in his stomach; it is the venom of cobras within him" (Job 20:14).

A possible example of the concept imagined here is the wicked person who attends court and swears an oath that he is telling the truth. However, he is lying. Revelation 21:8 includes unbelieving liars as among those who will end up in the lake of fire that burns with fire and sulfur.