From Matthew 12:22-30,
22Then they brought him a demon-possessed man who was blind and mute, and Jesus healed him, so that he could both talk and see. 23All the people were astonished and said, “Could this be the Son of David?”
24But when the Pharisees heard this, they said, “It is only by Beelzebub, the prince of demons, that this fellow drives out demons.”
25Jesus knew their thoughts and said to them, “Every kingdom divided against itself will be ruined, and every city or household divided against itself will not stand.
26If Satan drives out Satan, he is divided against himself. How then can his kingdom stand? 27And if I drive out demons by Beelzebub, by whom do your people drive them out? So then, they will be your judges. 28But if I drive out demons by the Spirit of God, then the kingdom of God has come upon you.
29″Or again, how can anyone enter a strong man’s house and carry off his possessions unless he first ties up the strong man? Then he can rob his house.
30″He who is not with me is against me, and he who does not gather with me scatters.
So Christ has announced that with His arrival into the world, the Kingdom of God has come. But He also makes it very clear that “Every kingdom divided against itself will be ruined.” So the Kingdom of God must not be divided against itself. The success of the Gospel depends on having One Church, rather than many churches vying to be the Kingdom of God on Earth.