Luke 14:23 NIV
“Then the master told his servant, ‘Go out to the roads and country lanes and compel them to come in, so that my house will be full.
This example is a bit unusual in that the text in question does not refute 'Christian' Nationalism, rather it is a text once used to support the suppression of dissenting voices within the Church through military force. In other words, Luke 14:23 was used historically on behalf of a Church Militant.
Saint Augustine is the third most influential person in Church history after two people whose names you will undoubtedly recognize: Jesus and the Apostle Paul. Most of Augustine's contributions were massively helpful to the Church, but there were exceptions {for instance: his negative view of sex even within marriage still ripples harming Christian marriages to this day}. The most dangerous idea that Augustine embraced was that it was fitting and proper for the Roman Empire, newly on the side of Christianity thanks to Constantine, to force the Donatists in North Africa with whom he contended on an issue of polity to rejoin the Church. His example of a militant Church authority would be used more than 1,000 years later to force Martin Luther to choose between rebellion and his understanding of God's Word.
The Donatist Controversy predated Augustine's time as the Bishop of Hippo, having arisen after the great persecution of Emperor Diocletian {303-305, 1/2 of all Early Church martyrs killed during those three years} when those who had refused to worship the Emperor (risking their lives) would not allow those who had recanted their faith under pain of death to return to the Church. Augustine sided with those in favor of forgiveness, hoping to heal the rift. After a pair of councils in N. Africa failed to reach a resolution, Augustine threw his weight behind the Emperor's willingness to use the army to enforce reconciliation.
This is one of the first examples of Christian on Christian violence in the name of unity, it happened in the very first generation in which Christian had civil/military power to wield against each other.
Was Jesus talking about Church unity in Luke 14:23? Hardly, that's not even on the radar when considering the interpretation of this parable. And yet, Christians (whether or not they deserve the 'Christian' caveat) have been willing through the centuries to wield scripture as a cudgel, backing it up with force, against those with whom they disagree. The Inquisition, the burning at the stake of Jan Hus, the slaughter of the people of Magdeburg, the City Council of Zurich drowning Anabaptists, the Puritans at Plymouth hanging Quakers, and so on, all following in the footsteps of the anti-Christian notion that faith can be compelled by threats and violence, that it can be protected or saved at the point of a sword.
In case you're wondering, the use of violence against the Donatists didn't work (it never does). Four centuries later when Islamic armies rolled across N. Africa the resistance to this invasion was weakened by a Church still divided against itself. Would kindness and patience have worked to heal the rift? That's the road not taken, we'll never know, but the use of force by Christians against Christians most certainly did not.