It costs something to be a real Christian, according to the standard of the Bible. There are enemies to be overcome, battles to be fought, sacrifices to be made, an Egypt to be forsaken, a wilderness to be passed through, a cross to be carried, a race to be run. Conversion is not putting a person in an arm-chair and taking them easily to heaven. It is the beginning of a mighty conflict, in which it costs much to win the victory.
A metallurgist is someone who can look at a platinum blonde and tell whether she's virgin material or a common ore.