God's will is that we Christians would be one and love one another.
John 17:20-22 (ESV)
20"I do not ask for these only, but also for those who will believe in me through their word, 21 that they may all be one, just as you, Father, are in me, and I in you, that they also may be in us, so that the world may believe that you have sent me. 22 The glory that you have given me I have given to them, that they may be one even as we are one,
John 13:34-35 (ESV)
34 A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another. 35 By this all people will know that you are my disciples, if you have love for one another."
But, even if we should be one, we should not be the same.
1 Corinthians 12:12-21 (ESV)
12For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ. 13For in one Spirit we were all baptized into one body— Jews or Greeks, slaves or free—and all were made to drink of one Spirit.
14For the body does not consist of one member but of many. 15If the foot should say, "Because I am not a hand, I do not belong to the body," that would not make it any less a part of the body. 16And if the ear should say, "Because I am not an eye, I do not belong to the body," that would not make it any less a part of the body. 17If the whole body were an eye, where would be the sense of hearing? If the whole body were an ear, where would be the sense of smell? 18But as it is, God arranged the members in the body, each one of them, as he chose. 19If all were a single member, where would the body be? 20As it is, there are many parts, yet one body.
21The eye cannot say to the hand, "I have no need of you," nor again the head to the feet, "I have no need of you."
The passage above makes hints that as we are different, we might start fighting and excluding different members. This actually had happened in Corinth, and this was one topic in 1 Corinthians.
1 Corinthians 1:12-13 (ESV)
12What I mean is that each one of you says, "I follow Paul," or "I follow Apollos," or "I follow Cephas," or "I follow Christ." 13 Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul?
To me it looks as though unity is very important. Of course there is still need for church discipline.