One lesson Everyman learned through his Christian life is that you should trust no one but God.
When Everyman dies and must face God's judgment, he desires a sign of fellowship and compassion from the Christian community, but finds himself alone and abandoned. With this, he realizes that only God is worthy of trust and only he can support people.
This lesson is one of the themes of the story and you can learn more about themes at the link:
https://brainly.com/question/4008478