The dynamic Christmas carol Joy To The World, by Isaac Watts, was based largely upon Psalm 98: "Shout joyfully to the Lord, all the earth, break forth in song...for He is coming to judge the earth, with righteousness He shall judge the world, and the peoples with equity."
Because of this, some say the song is not about Christ's birth in Bethlehem, but about Christ's second coming, and the future joy which will occur when He comes to set all things finally straight, in that full expression of His Kingship.
While I look forward to the second coming, Joy To The World makes sense to me as a celebration of Christ's first coming, too. While anticipating that full expression of His Kingdom-yet-to-come, we can celebrate His Kingdom-already-here.
Even prior to Bethlehem, I Chronicles 29:11 declared: "...all that is in heaven and in earth is Yours; Yours is the kingdom, O Lord, and You are exalted as head over all." Today? Psalm 103:19 says: "The Lord has established His throne in heaven, and His kingdom rules over all." Now? Acts 10:36 puts it in the present tense: "He is Lord of all."
Christ's Kingdom is not fully expressed on earth right now, that's for sure. There are weeds in His field, which He did not plant (Matthew 13). But the domain over which Christ is King (that is, His "King-domain"), includes both heaven and earth, right now. The whole field is His. The fact that not every human heart has received Him as King doesn't alter the fact that He is.
This is the world's greatest Christmas gift: that Christ came in human form “to make His blessings flow, far as the curse is found.” These blessings are flowing through redeemed people today who are reconciled to God, and reconciling all things to Him, including the things of earth, right now, far as the curse is found.
So by God's grace, let's occupy until He comes again, by pulling up bramble bushes and planting redwood trees before the second coming arrives, shall we? It's our essential occupation.
Maybe Joy To The World is one of those "both-and" songs, celebrating His first and second comings.
Joy to the Earth! The Savior reigns. Let men their songs employ, while fields and floods, rocks, hills, and plains, repeat the sounding joy!
Far as the curse is found.