Keith Simons explains Psalm 110, addressing the question of why the Messiah, as God's perfect king, is not ruling the world now. He emphasizes that the King James translators maintained the integrity of the Scriptures, believing in their divine preservation, and thus translated difficult passages literally. The psalm reveals that the Messiah is currently seated at God's right hand, ruling in the midst of His enemies while awaiting the time when all enemies will be defeated. Simons highlights the dual role of the Messiah as both king and priest, and the ultimate victory over evil forces that will come in the future. The sermon encourages listeners to understand the significance of the Messiah's current reign and the promise of His complete rule.