"Gospel doctrine matters because the good news is so full and rich and wonderful that it must be opened like a treasure chest, and all its treasures brought out for the enjoyment of the world. Doctrine is the description of these treasures. Doctrine describes their true value and why they are so valuable. Doctrine guards the diamonds of the gospel from the pirates who don't like the diamonds but who make their living trading them for other stones. Doctrine polishes the old gems buried at the bottom of the chest. It puts the jewels of gospel truth in order on the scarlet tapestry of history so each is seen in its most beautiful place."
-John Piper, God is the Gospel