Bible Question:

How can the churches become more united? God has called us to be a family. We do not get along well. If we all pray and truly love God, why do we not function better?

Bible Answer:

Unity is not possible among all of the churches for several reasons.

Unity At All Costs?

The major reason unity is not possible is due to doctrinal differences. Put another way-some churches disagree about what the Bible teaches. Some of the differences are serious and others are not. Unfortunately what one person considers serious may not be considered serious by another person. There are some today who believe that Christians need to ignore doctrinal differences and come together. But that is wrong. Listen to the following verses. It is a passage that many ignore.

Anyone who goes too far and does not abide in the teaching of Christ, does not have God; the one who abides in the teaching, he has both the Father and the Son. If anyone comes to you and does not bring this teaching, do not receive him into your house, and do not give him a greeting; for the one who gives him a greeting participates in his evil deeds. (NASB) 2 John 9-11

God has some strong warnings for those who want unity and are willing to ignore doctrinal differences. Notice that God starts this passage with “the teaching of Christ.” He is talking about everything related to Jesus. Then we are warned that anyone who does not agree with the truth about Jesus Christ should not be allowed into a Christian’s home. God goes on to say that if we even give them a greeting, we are sharing in their evil deeds. Unity is not possible with false teachers and false churches. God does not want this type of unity. It is called compromising the truth.

When Is Unity Not Possible?

God tells us that unity is not possible when we disagree about the teachings of Christ. Here are some of the teachings that we cannot ignore and a brief list of some who teach this error.

Scripture (NASB)MeaningWho Teach This?
By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God; and every spirit that does not confess Jesus is not from God; and this is the spirit of the antichrist, of which you have heard that it is coming, and now it is already in the world. 1 John 4:2-3False teachers are those who teach that the man Jesus Christ was not God.Mormons and Jehovah’s Witness are false teachers because they teach that Jesus was not God.
But avoid . . . men who have gone astray from the truth saying that the resurrection has already taken place, and thus they upset the faith of some. 2 Timothy 2:16-18False teachers are those who teach error about the prophetic future.This one is difficult because scripture is not always clear about the future.
But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons . . . men who forbid marriage and advocate abstaining from foods, which God has created to be gratefully shared in by those who believe and know the truth. 1 Timothy 4:1-3False teachers are those who teach celibacy and keeping the Old Testament laws regarding food.The Roman Catholic Church teaches celibacy and abstaining on certain days. The Seventh Day Adventists teach Old Testament food laws.
But even though we, or an angel from heaven, should preach to you a gospel contrary to that which we have preached to you, let him be accursed. Galatians 1:8False teachers are those who teach that a person is saved from his/her sins by doing good deeds and keeping rules.A number of groups teach this error: 1) those who say we must be baptized in order to be Christians, and 2) those who say that one can lose salvation if one does not continue in good works.

Conclusion:

Another reason unity is not possible in many churches or among the churches is that many churches contain leaders who are not really Christians. It is not good enough to claim to be a Christian. One must be a Christian. Are you a Christian?

Yet, God does call true believers to unity. A number of doctrinal differences are minor and should not be dividing Christians. How can we move toward unity? The answer is prayer, showing love toward others, and minimizing our differences where we can. We need to realize that all true Christians are our brothers and sisters in Jesus Christ.

And beyond all these things put on love, which is the perfect bond of unity. (NASB) Colossians 3:14

Reference Links:

Are You A Christian?
Have you ever talked with Mormons about Mormon doctrine?
How accurate is the New World Translation? - Jehovah Witnesses' Bible