What does Psalm 63:9 mean?

This song was composed in reference to David's evacuation during a rebellion (2 Samuel 15:13–14; 16:14; 17:27–29). Despite the danger, David expresses confidence in the Lord. He fully expects his enemies to be defeated. Figures of speech such as "go down into the depths of the earth" imply dead bodies in the grave. These are much like English expressions implying someone will be "buried" or "wind up six feet under." The Hebrew terms used are general and refer to the "lowest places." This connects to the Old Testament view of sheol: the underworld of the dead (Genesis 37:35; Psalm 55:15).

David believed in God's justice. He knew the Lord would judge those who lied about him and tried to kill him (Psalm 35). He declined to take justice into his own hands but left it in God's good timing. Ultimately, God did execute judgment on David's enemies. Second Samuel 18:6–8 reports that David's men killed thousands of the rebels' opposing army. Someday, those who oppose Jesus, the chief descendant of David, will feel the rod of God's punishment. Jude 1:14–15 predicts, "Behold, the Lord comes with ten thousand of his holy ones, to execute judgment on all and to convict all the ungodly of all their deeds of ungodliness that they have committed in such an ungodly way, and of all the harsh things that ungodly sinners have spoken against him."