I think you're not quite getting the message about what "one" means.

Unity, the totality of union, including one with the will of God.

St Paul "got it" as in Romans 15:6" "May the God of endurance and encouragement grant you to think in harmony with one another, in keeping with Christ Jesus, that with ONE accord you may with ONE VOICE glorify the God and Father of our Lord Jesus Christ."

It's the Scriptural ignorant that on the one hand demand Scripture (and only Scripture) for everything and on the other reject it when handed it.