Why do you have to split off?....
That grumpy man or lady in church who is always challenging the pastor decided not to leave.
The only thing that the passage tells us that there must be factions when the Word of God is taught... Those who have God's approval will know. And, those who do not have God's approval? Will only think they do (self righteousness).
Yes, it can work many ways.
Say a pastor is teaching false doctrines? Those who have God's approval will eventually get themselves up and leave that church.
But, what if a pastor teaches well and with integrity? Those who do not have God's approval usually try sticking around rather than leaving, wishing to stir up trouble with a desire to break up a church producing sound doctrine. Its the pastor's job in that case to show them the door.
Where there are believers with God's approval there will inevitably be factions formed.
Satan always wants to keep believers from the only thing that over powers him. Sound doctrine. That's what Jesus used when tempted by Satan. Jesus did not call down lightning. Jesus simply used... "It is written!" And, He knew what what was written was actually saying! (sound doctrine) Then?... Satan had to withdraw himself. "He departed."
"Resist the devil and he shall flee from you!" That means, keep taking in sound doctrine and growing in grace while the Devil will resist your advancement.... And, after you reach a certain point in growth and understanding? The Devil will not be able to bear the truth any longer. That is when he must flee.
Too few teach sound doctrine today. Instead, many follow the 'broad and wide' highway leading to destruction of their spiritual lives.
"For the time will come when people will not put up with sound doctrine. Instead, to suit their own desires, they will gather around them a great
number of teachers to say what their itching ears want to hear." 2 Timothy 4:3
Not a few! It says a GREAT MANY fake teachers who read from the Bible!