What was the importance of "the church" and the christian religion in the lives europeans in the middle ages?

Don't know if you still need this, but here is an answer:

There was little separation of church and state in the middle ages. Besides being royal or having a title, some of the highest ranks in society you could achieve were within The Church.

Additionally, performing certain rites and receiving different ordinances were some of the key ways monarchs could keep up appearances and have a positive reputation with their citizens and peers.