Paul wrote to the Romans about this obedience. This should not surprise us. Great men of God have always obeyed because they believed.
Faith is a stronger and more consistent motivation for obedience than fear.
They respond and conform to one or the either. There is no neutral ground. There is no hope for people that remain in that condition. Remember, acceptable obedience proceeds from faith. It is the result of being convinced of the truth and applicability of the message.