O KING OF THE NATIONS and the Desired of all, You are the cornerstone binding the two [i.e., Jew and Gentile] into one: COME, and save poor man, whom You fashioned out of clay.
The following commentary adapted from The Church’s Year of Grace, Fr Pius Parsch (The Liturgical Press, Collegeville, 1959):
Previous antiphons in this series stemmed from a Jewish background. The Messiah would be the fulfillment of Israel’s expectations, and Christians are the “wild vine” grafted onto the original vine of the Chosen People. In several of the antiphons, there are allusions to the conversion of the Gentiles, but this sixth antiphon is the first to address the Savior as “King of the nations and the Desired of ALL.” The reference to the “cornerstone” is to Isaiah 28:16, “Behold, I will lay a stone as the foundation of Zion, a tested stone, a cornerstone, precious and firmly set; if one believes, he will not be shaken.” On occasion, Christ called Himself the cornerstone (c.f. Matthew 21:42), indicating that He is the foundation, the spiritual support of the Church.
In our antiphon, however, the clause that follows indicates a function in reference to the Gentiles: the Messiah will be a cornerstone uniting both Jew and Gentile. This thought is from Ephesians 2:14, where Christ is called the peace-maker between Jew and Gentile, breaking down the wall of enmity between them.
The petition calls for the salvation of all humanity, which has its creation from the clay of the earth as a common bond. The antiphon should call all of us to work for the spread of the Gospel to all who have not yet heard it.