Why is Doctrine so Important?

The first epistle of John is written “to you who believe in the name of the Son of God, so that you may know that you have eternal life” (5:13). In order “that you may know,” the apostle presents three tests: the doctrinal test, the moral test, and the love test. On the place and importance of doctrine, Mark Dever writes,

I do not think that the church needs to worry about atheism today. That superstition has never seriously threatened the church of Jesus Christ. As a friend of mine once said, “The real danger is not unbelief, but wrong belief; not irreligion, but heresy; not the doubter, but the deceiver.” Wrong belief, heresy, and deceivers are what concern John.

. . .

When you share the gospel with others, you do not merely share your experience (though we certainly can share something about our own experience). Most fundamentally, you share objective truth. You share particular doctrines that are rooted in history about who Jesus is and what he did. You might decide this is not important, but then you would have to take 1 John out of the Bible.

—Mark Dever, The Message of the New Testament: Promises Kept