Only those with a pure, clean heart, will ascend the hill of the Lord and stand in righteousness with Him, which on our own is none of us. Psalm 24 makes clear that the only one’s to ascend the hill of the Lord are those possessing a purity beyond reach because of our depravity and having cut ourselves off from the life of the Trinity. What a sad thought.
But this is precisely why the rest of the Psalm the ancient gates and doors open for the revealing of the Holy One of God, the Son of God, Jesus, as the one who will and now has ascended the hill of the Lord.