Summary: The church is not invulnerable to the possibility of corruption. The church human leaders therefore corruption will exist. Learn to recognize it because then you can stop it.
The Pharisees started as a sect with a noble and perhaps a divine purpose. They were organized to resist the Hellenization of the Holy Land. The Seleucids wanted to change Galilee and Judah into a paradise of Greek Hellenism. The Pharisee sect was formed in 168 B.C.E. to combat this infringement on the people of the LORD. They were very successful in helping many Hebrews from losing their love of the LORD and turning to the Greek pagan Gods. Unfortunately, as the sect grew, corruption entered its core. When an organization learns that it can use its clout to oppress its people, corruption can enter the organization. It does not matter how large the organization is or might become. Corruption accompanies the organization once people learn that they can control other people by their wills. The goodwill of the Pharisees disappeared when they learned that they held a strong influence over the people that they initially tried to save. Corruption took the place of goodwill.
Unfortunately, this can be seen in all of human history. The church is no exception. It started with the noble purpose of spreading the Gospel of Jesus Christ. Unfortunately, over the centuries, it developed its own set of rules and regulations that are mainly outside the scope of the true meaning of the Gospel. The Reformation, which started in 1517, is a prime example of the people striking out against the Catholic Church's corruption. Today in 2021, there are numerous church denominations, all with their charters and books outside of the Bible, which define its members' beliefs and accepted behavior and allows for the exploitation of its members.
Jesus warns us not to fall into the same trap that the Pharisees and the Sadducees did. These were at one time reputable organizations that fell from grace. The LORD created each disciple of Jesus Christ to serve the LORD through His Messiah. Each disciple must ask themselves the question, "Are you doing that which is pleasing to the LORD?"
Our religious organizations were initially established to help people worship and praise the LORD. However, when the rule book is larger than the Bible, the members have to ask questions. For example, I have a Methodist Episcopal church Discipline, the definition of what Methodism was, from 1836. It is a small book, 2" x 3" x ¼". Today's United Methodist Disciple is enormous, being 5.5" x 8.5" x 1”. So why is there a need for so many rules and regulations? That is what the members need to ask.
May the LORD bless you in your learning and studying of His Word.