What we believe has fundamental effects on how we live our lives, what we allow to influence us as truth has the same effect. The early church became, rightfully, protective over what was being taught as sacred scripture.
Marcion was guilty of attempting to reduce the Gospel to simply the love of Christ. He removed all parts of the Bible that were Jewish in nature and attempted to conform the Bible to his own worldview (sounds like the culture we live in today, right?) When he neglected the wrath of God he also eliminated the need for grace. Our sin is real, and it is ugly. It is true that God loves us, but if you recall, the wages of sin are death.
Montanus believed that what he felt, thought, and became emotional
over was more important, and held greater truth, than what God had
revealed to humanity through Jesus’ own words and the apostles words.
Our culture today is a “me” based culture that takes this approach to
everything. We say things like “follow your heart” and “do what you feel is
right” in regards to decisions we make…yet the scriptures teach us that
many times that is the worst way to make a decision.