We all want unity. No one wants schism, pain, or the resentment that comes from disunity. We live in an age that exalts "inclusivism," the attempt to include all and exclude none.
But, "inclusivism" as a goal is a problem for Christians. The gospel divides. It divides families. "And Saul spoke to Jonathan his son and to all his servants, that they should kill David. But Jonathan, Saul’s son, delighted much in David" (1 Sam 19:1). The presence of David, God's anointed, divided Saul's family. David didn't want this. David didn't seek it. He wanted to be friends. However, God's anointing on his life separated people into two camps, those for and those against him.
So it is today. We cannot be good stewards of the gospel and and make inclusiveness our goal. Jesus warned us that this would be the case. "If anyone comes to me and does not hate his own father and mother and wife and children and brothers and sisters, yes, and even his own life, he cannot be my disciple." (Luke 14:26).
The gospel also provokes persecution from those we love the most. "Do you think that I have come to give peace on earth? No, I tell you, but rather division. For from now on in one house there will be five divided, three against two and two against three. They will be divided, father against son and son against father, mother against daughter and daughter against mother, mother-in-law against her daughter-in-law and daughter-in-law against mother-in-law.”" (Luke 12:51-53).
If our gospel never divides or alienates it might signal unfaithfulness. The message that Jesus loves you and has a wonderful plan for your life does not alienate . What alienates is what Paul called the "offense of the cross" (Gal. 5:11), the doctrine that God is holy and demands perfection, that the wrath of God rests upon all men who reject this gospel, that the gate into Heaven is narrow, and few enter through it. If this is the case, human effort cannot make us right with God. Only faith in what Christ has done for us through his death and resurrection can close the gap between God and man.
Ironically, great unity, great inclusiveness belongs to those that embrace this "offense." This is the unity Jesus sought when he prayed "that they may be one even as we are one" (Jn. 17:13).
In the spiritual world painful division always precedes true unity.