Psalm 17:4 (ESV)
4 With regard to the works of man, by the word of your lips I have avoided the ways of the violent.
This is a part of speech known as a metonym, where a word is used as a substitute for something else with which it is closely connected (for example, head of cattle,
where head
refers to individual cattle and not just their heads). Lips
refers to what David says, which issues from his heart.
1 Hear a just cause, O LORD; attend to my cry! Give ear to my prayer from lips free of deceit!