The clergy was very important to society for the serfs because they were the ones that comforted the serfs in times of trouble and taught them the teachings of God which the serfs tried to follow. The Church was also a place of refuge in times of war and in return, the serfs would pay with a bit of their produce.
The clergy would often help the king make suggestions on how to rule over his the land split up into manors, where to attack to conquer, and etc., therefore, the clergy can make him do whatever they wanted. And like the serfs, the king would go to Church for comfort and praying. The kings were also usually illiterate so they would call on bishops and such to write documents for them
Hah, this illiterate doesn't know this is true since she can't point it out in the Holy Bible. Since she is my enemy, I can excommunicate her.
Lastly, the Church affected the clergy because the Church gave those who would serve it and God, therefore, giving them a lot of power since everyone wanted to go to heaven and would always listen to the clergy. Members of the clergy were also educated so people who disagreed couldn't point out something wrong with what they said. The Church is also the place where ceremonial rituals are to happen with members of the clergy participating in it.