What does Psalm 9:8 mean?

This continues David's praise of God for His perfect wisdom and judgment (Psalm 9:7). The depiction here agrees with other statements made in the book of Psalms (Psalm 96:10; 98:9).

God's Son, Jesus Christ, shares the throne with the Father. Hebrews 1:8 declares, "But of the Son he says, 'Your throne, O God, is forever and ever, the scepter of uprightness is the scepter of your kingdom.'" Someday, Jesus will rule the world and judge its inhabitants with uprightness, as David has already depicted of God in the previous verse. Matthew 25 pictures Jesus seated upon His throne and judging the Gentile nations. He will separate the sheep from the goats, and although many will contest His verdict of guilty, Jesus will provide evidence of their guilt.

Isaiah predicted Jesus' righteous rule over all the earth. Isaiah 9:7 declares there will be no end to Jesus' government and peace. From the throne of David, He will establish and maintain His kingdom with justice and righteousness forever. When He returns to earth, Jesus will rule with a rod of iron (Revelation 19:15). Every knee will bow to Him, and every tongue will confess that He is Lord (Philippians 2:10–11).