Basis of Doctrine
There are many religions in this world and also many pastors and priests and many other leaders of various religion. The hierarchy or family tree of those religions is also known and could be explained. Most of the religions that exist now have common characteristics and that reveals what is their identity. It reveals who is their family member or their origin. The number of years of existence as a religion does not prove the legitimacy of a church but rather the doctrine that they follow.
Thoughts of people vary especially when they think they are right in their conclusion. That is why it resulted in various branches of religion. Through those process, the truth is now mixed with the teachings and practices of people. It is just like in the time of Jesus. Jesus preached the gospel until He died. Many people believed in Him as the apostles preached to them. But there are people who are teaching other doctrines that come from their own thoughts. It should not happen as only God has the authority to changed and interpret.
God did not give authority to anyone to put his thoughts and teach it to others but God only wants His people to follow His commands. That is why He already put in the Bible that He will destroy the world because people do not keep His commands. God chose His people and lead them out of slavery. He gives His promise but He tested their hearts first if they will follow His commands or not. It is the same even to this day.