“Lift up your heads, O gates! And be lifted up, O ancient doors, that the King of glory may come in. Who is this King of glory? The Lord, strong and mighty, the Lord, mighty in battle! Lift up your heads, O gates! And lift them up, O ancient doors, that the King of glory may come in. Who is this King of glory? The Lord of hosts, he is the King of glory! Selah” -Psalm 24:7–10
These final verses signify a marked transition in the progression of the Psalm. It’s not a shift, per se. Rather, a fulfillment. The psalm moves from anticipation to realization, from contemplation to activity.
In verses 1-6, the proclamation of The Lord’s sovereignty over all creation, his sole preeminence in the worship of Israel, and the requisites for approaching his throne and receiving his blessing are contemplated.
In verses 7-10, the psalmist cries out with a call to action! In a poetic refrain, he gives an exhortation for all Zion to receive their King of glory! One might imagine a royal procession led by priests carrying the ark of the Covenant approaching the city after a triumphant battle.
The gates either refer to those who sit at the gates in governing positions or the actual gates themselves. The ancient doors are literally the gates of the city and thus the psalmist is highlighting the significance of his glorious return from battle in the form of a parallelism.
The question is then raised, almost rhetorically, so that it can be announced. Who is this King of glory? It is the Lord who is strong and mighty in battle. The parallelism is repeated again as a refrain, but culminates in the ultimate declaration of The Lord’s glory: He is the Lord militant, the King of glory.
That is, The Lord is sovereign over the nations and he is advancing his kingdom until it stretches from sea to sea and cover the earth.
“Of the increase of his government and of peace there will be no end, on the throne of David and over his kingdom, to establish it and to uphold it with justice and with righteousness from this time forth and forevermore. The zeal of the Lord of hosts will do this.” -Isaiah 9:7
“For the earth will be filled with the knowledge of the glory of the Lord as the waters cover the sea.” -Habakkuk 2:14