What does gold mouth and silver teeth mean?

Golden mouth and silver teeth mean that the emperor or noble person speaks heavily, which means that he is what he says. Gold mouth and silver teeth are now compared to uncompromising people.

Source: Jin Xiahou Zhan's "Arriving at Doubt": Today's golden mouth is quiet and silent. Explanation: Gold and jade are precious metaphors. It means that the emperor has a golden mouth and jade teeth, and what he says cannot be changed.