As you look upon photographs of the earth taken from outer space, you should notice something of significance. Between the nations, one cannot distinguish borders. Only those boundaries formed by natural means, such as rivers and oceans, can be seen. There are no lines drawn upon the earth. Yet, in our sinfulness, we humans set boundaries between nations and peoples.
Isaiah prophesied that God would speak his Word through peoples of many nations. Paul reminds the Gentiles they were once outsiders in relationship with God. Yet, Jesus Christ, the cornerstone upon which the foundation of the Church is built, has brought us near to God.
The Messiah is the cornerstone upon whom our spiritual foundations are laid, but on whom unbelievers continue to stumble (Matt. 21:42). This cornerstone unites and binds those who believe, the Jew and gentile, into one, making peace between them (Eph. 2:10-16). And so with the six antiphon in the Octave of Christmas, the Advent Church sings:
O come, O King of Nations come,
O Cornerstone that binds in one;
Refresh the hearts that long for you;
restore the broken, make us new. Rejoice!
O Come, O Come Emmanuel v. 7 Traditional