The “O” Antiphons, the seven jewels of our liturgy, date back to the fourth century; there is one for each day from 17th to 23rd December. These antiphons address Christ with seven magnificent Messianic titles, based on the Old Testament prophecies and types of Christ. The Church recalls the variety of the ills of man before the coming of the Redeemer. They are fervent prayers asking Our Lord to come to us.
“Before the coming of God in the flesh, we were ignorant, subject to eternal punishment, slaves of the Devil, shackled with our sinful habits, lost in darkness, exiled from our true country. Hence the ancient antiphons announce Jesus in turn as our Teacher, our Redeemer, our Liberator, our Guide, our Enlightener and our Saviour.” — The Golden Legend of Jacobus de Voragine, trans. Ryan and Ripperger, 1941
The antiphons beg God with mounting impatience to come and save His people. The order of the antiphons climb climatically through our history of Redemption.
“In the first, O Sapientia, we take a backward flight into the recesses of eternity to address Wisdom, the Word of God. In the second, O Adonai, we have leaped from eternity to the time of Moses and the Law of Moses (about 1400 B.C.). In the third, O Radix Jesse, we have come to the time when God was preparing the line of David (about 1100 B.C.). In the fourth, O Clavis David, we have come to the year 1000. In the fifth, O Oriens we see that the line of David is elevated so that the peoples may look on a rising star in the east, and hence in the sixth, O Rex Gentium, we know that He is king of all the world of man. This brings us to the evening before the vigil, and before coming to the town limits of Bethlehem, we salute Him with the last Great O, O Emmanuel, God-with-us” (from He Cometh by Fr. McGarry).
O REX GENTIUM (22nd December)
O King of the Gentiles,
and the Desired of all nations(Hag 2:8),
you are the cornerstone (Is 28:16)
that binds two into one (Eph 2:14).
Come, and bring wholeness to man
whom you fashioned out of clay (Gen 2:7).
The Desired of All Nations Shall Come
Today we lift our voices to Christ, calling him King of the Gentiles and the Desired of all nations. The O Antiphon draws upon the second chapter of the prophet Haggai. With the temple still in ruins after the Babylonian exile and the project of rebuilding it daunting, Haggai speaks a word of comfort to Zerubbabel, the governor; to Joshua, the high priest; and to all the remnant of the people:
“And the Desired of all nations shall come; and I will fill this house with splendour, says the Lord of hosts. (Hag 2:8)
By calling the Messiah the “Desired of all nations,” Scripture and the Sacred Liturgy recognise the aspirations of every nation and culture towards the good, the true, and the beautiful, as aspirations towards Christ. In every culture there are traces of a mysterious preparation for the Gospel. Every time a human being seeks the splendour of the truth, the radiance of beauty, the purity of goodness, he seeks the Face of Christ, the “Desired of all nations.” When the missionary Church proclaims Our Lord Jesus Christ, she is proclaiming the “Desired of all nations.”
(Read today’s article on Vultus Christi for a fuller explanation of today’s Antiphon.)
The Nations followed God’s chastisment of Babel.
Genesis 11 
And therefore the name thereof was called Babel, because there the language of the whole earth was confounded: and from thence the Lord scattered them abroad upon the face of all countries.
Babel means confusion. From this confusion of languages came the Nations.
Our Lord came to repair for the Sins of Man and reverses Gods anathema’s. The existence of the Nations means that there is not a common language on Earth. God is to judge the Nations
Jeremias (Jeremiah) 25:31
The noise is come even to the ends of the earth: for the Lord entereth into judgement with the nations: he entereth into judgement with all flesh; the wicked I have delivered up to the sword, saith the Lord.
So there is great significance in the Antiphons and the Triumph of The Faith fortold at Fatima.
The Judgement of the Nations comes with the defeat of Babel.