Enter in! O Enter in!

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 ESV)

24:7-10 The splendid entry here described, refers to the solemn bringing in of the ark into the tent David pitched for it, or the temple Solomon built for it. We may also apply it to the ascension of Christ into heaven, and the welcome given to him there. Our Redeemer found the gates of heaven shut, but having by his blood made atonement for sin, as one having authority, he demanded entrance. The angels were to worship him, Heb 1:6: they ask with wonder, Who is he? It is answered, that he is strong and mighty; mighty in battle to save his people, and to subdue his and their enemies. We may apply it to Christ's entrance into the souls of men by his word and Spirit, that they may be his temples. Behold, he stands at the door, and knocks, Rev 3:20. The gates and doors of the heart are to be opened to him, as possession is delivered to the rightful owner. We may apply it to his second coming with glorious power. Lord, open the everlasting door of our souls by thy grace, that we may now receive thee, and be wholly thine; and that, at length, we may be numbered with thy saints in glory.

Matthew Henry's Concise Commentary on the Bible