What does Psalm 20:9 mean?

This psalm began with a prayer from the congregation (Psalm 20:1–5), and it ends with one, as well. In unison the congregation of Israel prayed for David's deliverance from his enemy. The congregation called on the Lord to answer their prayer and save the king. With a repeat of that basic theme, the psalm ends as it began. The people of Israel bowed to the sovereign King—God, the Lord—and looked to Him for victory.

David was an earthly king, but he acknowledged the Lord is the King of glory. In Psalm 24:10 he writes, "Who is this King of glory? The LORD of hosts, he is the King of glory!" Psalm 95:3 proclaims, "the LORD is a great God, and a great King above all gods." Like the congregation that prayed for David, believers ought to keep in mind that the person to whom they pray is the sovereign King of the universe. Nothing is impossible with Him (Luke 1:37). No burden is too heavy for Him to lift. No problem is too big for Him to solve. No barrier is too strong for Him to break down. And He answers when we call on Him (Jeremiah 33:3; Matthew 7:7–8; Hebrews 4:14–16).