It is clear from the Lord's final recorded prayer before going to the Cross (Jn. 17), that Jesus wanted believers to be in unity, in harmony, to be one (v 11, 21-23). After all, the oneness of the Body of Christ is what Jesus said would convince the world that God sent His Son (v. 21), "and that the world may know that Thou hast sent Me, and hast loved them, as Thou hast loved Me" (v. 23). Not only does God love the world enough to send His Son to die for it (Jn. 3:16), He loves the world with the same love He has for His Son!" I guess when the Word says that God is no respecter of persons (Acts 10:34), He really isn't! God doesn't play favorites, even when it comes to His Son. When the sin of mankind was placed upon Him, He had to die!
The Apostle Paul emphasized unity in Ephesians 4:1-13. He gave the formula for maintaining unity (v. 1-3). He presented seven examples of oneness, and included the Body of Christ (v. 4-6). Finally, he explained that the duty of the leaders of the Church was to teach until "we come in the unity of the faith, and of the knowledge of the Son of God" (v. 11-13).
So, if it is God's will that believers be one, when is division of any kind good? Separation of believers is good when it involves sending out soul-winners into a lost world (Acts 13:2). Separation of believers is good when a brother is walking in sin (Matt. 18:15-17; 1 Cor. 5:1-13; 2 Thes. 3:6, 14), but this separation must be motivated by a desire for his repentance, and reconciliation with the Church (Matt. 18:15).
There is another division that is not only good, it is absolutely necessary if there is to be unity in the Body of Christ. In 2 Timothy 2:15, Paul wrote, "Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth." The main reason for division in the Body of Christ is sin. We pridefully need to be right, we are too lazy to do the work of study, and we definitely lack love for the brethren.
God's Word needs to be rightly divided in order to make sense out of what some believe to be contradictions. For example, there are eight covenants in the Scriptures. There are seven dispensations. There are two resurrections, the first being divided by specific times. There are two Advents of Jesus Christ, the second being divided into two parts: the Rapture, and the Glorious Appearing. There are also five judgments.
Tomorrow, Lord willing, I will give the references for each of these divisions.