John Piper from Desiring God says unbelievers have the voice of God in their hearts. Ask yourself. Isn't this leading people to listen to their own hearts and not the Bible? "The heart is deceitful above all things." (Jer 17:9). Are Piper's comments supported by Romans 1 or Romans 2? No. See... http://Godnoliar.com/rom1.htm and http://Godnoliar.com/rom2.htm
Response to Tim Mcneely : G'day Tim! Thanks for your feedback. You're right that Romans 1 says everyone knows about God. But the question is HOW do they know about God. Do unbelievers 1) have the knowledge of God deep down in their hearts (as Piper says) or 2) do unbelievers merely HEAR about God. Now, Piper teaches point #1, that is -- unbelievers deep down know the True God created the worlds.
But how does Piper deal with Hebrews 11:3? This verse says it is by FAITH we understand the worlds were framed by the Word of God. And unbelievers do NOT have faith. Therefore unbelievers do NOT understand the worlds were created by God.
Take for example Arminians who say that a man created the world. Their god is a changeable, weak, helpless being (a man) that cannot do what he wants to do. He wants everyone to be saved but utterly fails to accomplish what he wants. So they believe a pathetic idol/man created the worlds. Deep down they have NO IDEA who the True God is, because he is the opposite to their god -- the true God "works all things according to the counsel of his own will" (Eph1:11), "creates evil" (Isa45:7) and who achieves everything he wants.
Clearly most people think a man created the worlds. If they think otherwise, why do they always depict their "god" as a man? Moreover, why does their "god" act just like a man? Their god only saves people who are first "accept him" but rejects those who "reject him". This is not a divine being but a being that operates just like humans.
The True God is totally different. "The nations which sought after unrighteousness have obtained righteousness" (Rom 9). He is the only being who requires ...