Dictionaries define an idol as "any object of ardent or excessive devotion or admiration." If we obey the dictates of a person, church, or some other group contrary to the direct commands of God, we are guilty of idolatry. The individual or group becomes the idol, replacing God.
This section reveals that speaking the same thing is a choice. We have to choose for the sake of unity. It is not an option for those who consider themselves to be converted; it is commanded. There is no option. We have to choose to follow Christ.