Warning: Bible scripture will be dealt with in this text.
It may seem like there are many opposing flavors of Christianity, but in fact there is only one faith[1]. Once they walked in one accord [2], and were identifiable by how they loved one another[3]. Sadly these traits are lost or watered down in denominationalism. Divided by teachers[4], traditions[5], and other forms of legalism.
At a fundamental level Christians agree on one point, Jesus is Lord. That can be asserted because it's fundamental to the very definition of what it means to be Christian. It would be difficult to deny this doctrine and still claim Christianity.
Romans 10:9 because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.
The phrase, "Jesus is Lord" communicates different things to different hearers. To the Jewish hearers it spoke of the deity of Christ. To the Roman it was seditious talk.
"At age eighty-six, Polycarp, the second-century bishop of Smyrna and disciple of the apostle John, was brought to the Roman authorities and ordered to confess that Caesar is lord. Though doing so would have saved his life, Polycarp refused and was murdered, inspiring others to remain faithful."
So while many Christians today repeat this phrase, few do so are apprehended by the fullness of His glory nor with the depth of gravitas it carried for the earliest Christians. This undermined the "politics" of the day, and as a result caused many Christians to suffer the penalty of death.
When Christians truly comprehend the meaning of "Jesus is Lord" they'll get along better with other saints and not be such friends of the world [6], or it's governments.