Psalm 9 teaches an unexpected kind of thanksgiving—giving thanks not only for what God has done, but also for His future justice. David resolves to praise God because the Lord is the righteous Judge who defends the oppressed, defeats their enemies, and never forgets His people. Even in hardship, believers can give thanks with confidence, looking back to the cross, trusting God's care in the present, and rejoicing that Christ will return to judge the nations and make all things right.