"Why do there have to be denominations?"
"But if one is inclined to be contentious, we have no other practice, nor have the churches of God. But in giving this instruction, I do not praise you, because you come together not for the better but for the worse. For, in the first place, when you come together as a church, I hear that divisions exist among you; and in part I believe it. For there must also be factions among you, so that those who are approved may become evident among you" (1 Corinthians 11:16-19).I've heard two different pleas for unity lately, one in a letter to an editor in a state newsmagazine, and another from a keynote speaker at a national convention. We've all heard lots of pleas for unity, and it's usually a unity that means "accept everything from everyone" or "let's unite under my authority and/or viewpoint." I gotta say: I'm not always interested in unity.
I'm not interested in unity with those who minimize a deep, biblical understanding of Jesus, eternal Son of God and son of man. I'm not interested in anything less than His utter Sovereignty. I'm not interested in unity with those who regard the Bible as merely man-created or outdated or live a pragmatic denial of its truth by their lifestyles and choices. I'm not interested in unity with those who think "conversions" fulfill the Great Commission rather than disciple-making. I'm not interested in unity with those "Christians" who think they can have a vibrant faith apart from the Body of Christ. I'm not interested in unity for the sake of unity unless it is a unity under Christ the Head of the Church with His Word and Spirit being the final and absolute authority.
Christ creates division. He is the Ultimate Catalyst. When He says, "blessed is he who does not take offense at me" (Matthew 11:6), it's because there's a real probably that you will be offended by the real Jesus! It takes a supernatural intervention in your heart for you NOT to be offended at Him. He is the Offense, as is the message of His cross (1 Corinthians 1:23). Are you blessed, or have you tried to tame the Lion of the Tribe of Judah?
"There must be factions among you..." From the solid standing of the Rock of the Word, I will love you, answer your questions, work for your good, etc. But I will not leave this place in which I stand. I will not argue with you, will not hate you, will not slander you, etc. But I will not join you if you stray into a swampland in Babylon. And I will not allow you to poison the flock I have been commanded to shepherd.
Approval comes through God in Christ, revealed by the work of the Holy Spirit in the midst of the Church, and His singular instrument of working in the midst of His Church is His Word. That is the approval manifested by division.
There will be unity when people gather before God to be taught by Him, not to re-make Him into a mirror image of our contemporary sensibilities and desire to be the center of the universe (Isaiah 2:2,3). The "swords" and "spears" will be beat into "plowshares" and "pruning hooks" not when humans come together in their own strength and wisdom, but when they are utterly and completely conquered and subdued by the LORD (2:4).
Want unity? Be consumed by the Offense.