What does it mean to have an iron lock in fortune telling?

Can you believe my son can't bring gold and silver jewelry?

Eight-character fortune-telling has been called "golden snake and iron lock" since ancient times. It is forbidden to wear gold and silver ornaments, and it is not invented by modern fortune tellers to deceive people. This "golden snake and iron lock" life is equivalent to the modern saying "ADHD". Curious about everything in your mouth is asking for trouble. In order to prevent accidents, fortune tellers fabricated a somewhat scary "golden snake" and "iron lock" to warn people. Don't be willful if you have money. You would rather believe it. Life is more important than gold and silver.