The psalm begins with a declaration of God's greatness - how all of the earth is His.
The second part asks the question - Who can be in God's presence?
With the answer being "those with clean hands, pure hearts, don't trust in idols and instead seek God's face.
The last part calls for a grand celebration as the King of Glory enters Jerusalem!
This grand celebration is actually a two-part celebration. The first part has already taken place. When Jesus entered into Jerusalem during His triumphal entry He entered through the Eastern Gate.
There is a lot of really cool information about the Eastern Gate - also called the Golden Gate on Wikipedia that you can see here Golden Gate (Jerusalem)
Ezekiel prophesied that Messiah would enter through the Eastern Gate. What's really cool about this prophecy is that the Muslims in the year 810 and then an Ottoman Sultan in 1541, in their efforts to prevent the Messiah from entering Jerusalem actually helped fulfill part of the prophecy.
When Jesus Christ returns He will open that gate - I picture it just crumbling before Him (The whole earth is His after all) - and He will enter Jerusalem as the King of Glory.
What does this mean for us today? (Bottom line)
God is worthy of our praise because the whole earth is His - including all who live in it!
For us to be in God's presence we need clean hands, a pure heart and need to seek Him. This is possible because of Jesus forgiving us of our sins and us living a holy life.
We can look forward to His second coming when all the world will see Him as the great King of Glory!