God will reveal himself to anyone truly seeking the truth. Even if they don't start looking for the Christian God, he will reveal himself, be it through visions or dreams or missionaries. He has given everyone a starting point. http://bible.com/100/rom.1.19-20.nasb because that which is known about God is evident within them; for God made it evident to them. For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.