1 Great is the Lord, and most worthy of praise, in the city of our God, his holy mountain.
2 Beautiful in its loftiness, the joy of the whole earth, like the heights of Zaphonis Mount Zion, the city of the Great King. 3 God is in her citadels; he has shown himself to be her fortress.
This psalm starts with the phrase "Great is the Lord." Praising God for his greatness is something we can do forever. Why? God is great. Greater than any man. God is the greatest, there is no other god(s) that can compare. God is great in Himself.
Then, the psalmist describes the place where the Israelites worshipped the greatness of God. The place was Jerusalem, which was at a high elevation, about a half mile up in the city itself, and higher in other places. This height gave the temple an overview of the greatness of God's creation and that He is Lord over it. It also gives allusion to the future city of God, often called the New Jerusalem. As one commentator wrote,
"This reminds us that though the psalmist certainly had the literal, historic city of Jerusalem in mind he was also carried away by the inspiration of the Holy Spirit to also see the idealized city of Jerusalem, the city of God, the New Jerusalem (Revelation 3:12 and 21:2). The two aspects do not cancel each other out; they compliment each other."
In Revelation, the vision given by John is that worship will be a constant activity in heaven. The picture is given of thousands upon thousands of angels and living creatures worshipping Jesus on the throne saying, "Worthy is the Lamb who was slain to receive glory, might and honor forever and ever." Revelation 5:6-8
As you worship not only remember that "Great is Lord and worthy to be praised", but also anticipate the day you will cry out with thousands upon thousands in heaven day and night crying "Worthy is the Lamb who was slain!