To begin, I believe that when people of all nations come together in worship, we are witnessing to the power of the gospel. In Ephesians, Paul states the church reveals the wisdom of God to the rulers and authorities in the heavenly places (Eph. 3.9-10). No doubt, part of what Paul is describing here is a church of Jews and Gentiles who have come together in peace--"For he is our peace; in his flesh he has made both groups into one and has broken down the dividing wall, that is, the hostility between us" (Eph. 2.14). Here we see the church showing the world what God wants the world to be like, for at the end of the time, the nations walk in the light of the glory of God (Rev. 21.24).
All of this reminds me of a challenge the early Christians faced. Many of their opponents knew the prophecies of the Old Testament. They argued that many of these prophecies are unfufilled so Jesus must not be the Messiah. The opponents argued from a passage like Isaiah 2.1-5 that when the Messiah comes, there must be peace among the nations. But look around, these opponents continued, there is no peace among the nations, therefore, Jesus is not the messiah.
The early Christians responded by saying, You're wrong, look at the church, there you'll find people coming together from different tribes and languages to worship the one true God in glory. In responding to an opponent who utilizes the Isaiah 2 passage against the Christians, Origen states:
"This house is exalted 'above the hills' which are those men who seem to profess some exceptional ability in wisdom and truth. 'All nations' are coming to it, and 'many nations' go, and we exhort one another to the worship of God through Jesus Christ which has shone out in the last days, saying: 'Come, and let us go up to the mountain of the Lord and to the house of the God of Jacob, and he will proclaim to us his way and we will walk in it.'"
Similarly Justin wrote in the second century the following:
'That this prophecy [Isaiah 2.1-5], too, was verified you can readily believe, for twelve illiterate men, unskilled in the art of speaking, went out from Jerusalem into the world, and by the power of God they announced to the men of every nation that they were sent by Christ to teach everyone the word of God; and we, who once killed one another, [now] not only do not wage war against our enemies, but, in order to avoid lying or deceiving our examiners, we even meet death cheerfully, confessing Christ."
The early Christians pointed to the church as proof that the Messiah had come. In the church, there should be peace among the nation; and when there is, we show the world what God intends for the world. We become an appetizer to the great heavenly banquet.
So I hope that you share this vision, and that you want to build up the church, by learning to love all people from all nations. This is our call, this is our task.
Peace.
