Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment. 1 Corinthians 1:10 KJV
It takes a common understanding and obedient life application of the Word of God for there to be unity amongst the people.
Our great nation found its cohesiveness in the fact that, despite differences of personal opinion, the people were, for the most part, biblically knowledgeable and willing to live by its dictates.
Can two walk together, except they be agreed? Amos 3:3 KJV
Nothing pleases God more than to see His people walking in love.
Fulfil ye my joy, that ye be likeminded, having the same love, being of one accord, of one mind. Let nothing be done through strife or vainglory; but in lowliness of mind let each esteem other better than themselves. Look not every man on his own things, but every man also on the things of others. Philippians 2:2-4 KJV