What is at the core of sin?

From the Shepherd's Scrapbook blog site:

What is the core sin of the human heart? Is it pride? Is it the sin of unbelief? Theologians have debated this topic for centuries. But According to Dr. David Powlison, the sins of pride and unbelief are really “two doors into the same room.” And he adds a third door—the fear of man.

These three core sins are interrelated, and it’s not difficult to see how. Pride is the act of installing myself as the king of my own autonomous kingdom. Unbelief is the act of erasing God from my kingdom (functionally, if not deliberately). Fear of man is the act of installing other sinners as big players in my kingdom (When People are Big and God is Small).

And it’s no surprise that all of the lies and lusts of our hearts are to be found rooted in these three core sins. These lies and lusts are expressions of the three core sins.