There is a conference called Together for the Gospel. What an apt title though in general for the work of the Spirit of Christ among God's people? God calls people from every tribe, tongue, and people group. More than any conference, the gospel crosses barriers beyond backgrounds and countries of birth and denominations. So when the church assembles anywhere in the world, it is a refreshing thing, because God overcomes barriers that man or woman might set up such as "how they were raised," and instead replaces our petty issues with the greatness of His Son, Jesus and the doctrine of His person.
It is a great reminder in Scripture when Paul, a Jewish educated semi-well off man in seasons of life, writes to his friends the Philippians from the city of Philippi who were doing ok, but definitely not Jewish, "therefore my brothers whom I love and long for, my joy and crown, stand firm thus in the Lord, my beloved." He speaks as if they are family, though they are from very different cultures and backgrounds. He speaks as though they have value, though people naturally in the world do not value those who are different.
Paul is able by focusing on Jesus Christ to love those unlike him in so many ways. He can then ask two people who do not get along, to get along, in the Lord right after that Scripture. He can say "let your reasonableness be known to everyone. The Lord is at hand...." Wow. Such a radically different picture we see here, of unity around Jesus Christ. It is a great application to our lives to live this out.
Likewise Jesus in what we have recorded of his living Word in the Gospel of Luke, says in chapter 7, verses 36 to 50, that the woman who was a "sinner" is welcome to come to worship Him as Savior. She is completely (verbal form meaning started and continues indefinitely with effects to present tense) forgiven of all her sins (same for us once we believe, forgiveness continues). She is an outcast in society, and yet she manages to get into a place where Jesus is, where she would not be welcome in that home, but Jesus welcomes here. He commends her example of stepping out in faith to worship, despite a societal reason she would not be accepted. She wanted to be where Jesus was at work. May that not be a great thing to be said about all of us? Wow.
Clearly the most common proof of this gospel bringing people together is the command to take the good news to all peoples (or all nations). As the gospel is in every nation, it is typically taken that Matthew 28 refers to all people groups. We are to teach people to worship God, no matter their place or family or country. How amazing is that. God is truly a great and awesome God to unite completely disparate people groups in worship. Amen.