If you have a bumper sticker on your car that proclaims your faith, don't drive like a jerk. If your car has a sticker that reads "Jesus," "NOTW," "Blessed to be a Blessing," "Harvest," "The Grove," "I Found It," "Jesus Saves," "In Case of Rapture, Car's Yours," "My Boss is a Jewish Carpenter," or "Follow me to (Insert Church of Choice Here)" be polite and obey the law. Don't cut people off, change lanes without signalling, wave with an extended middle finger, or my personal weakness, speed.
If you choose to put a sticker on your car that proclaims the King James Version of the Bible is the only divinely inspired English Translation or one that implies real Christians only attend church on Saturdays, drive however you like. Nobody cares.
I don't have any stickers on my car.