Faith is not about believing only in certain doctrines and practices. It is an actual revelation, acceptance and intimacy with another person: Jesus. We believe more than facts and beyond reason. We are fully in a relationship that is personal and living. It is communion and participation. Otherwise our faith is based on knowing right stuff, people, catechisms, groups and traditions.
Irenaeus (130-202AD) early church father wrote:
“The heretics who have perverted the rule of truth, preach themselves when they believe that they are preaching Christianity”
Man-made doctrines and theologies are heresy. I think this happens when we preach ourselves instead of Christ. We must have a revelation of Jesus if we are to know him in the Spirit.
“And this is the way to have eternal life—to know you, the only true God, and Jesus Christ, the one you sent to earth.” Jesus