Mouth of gold; break the mold
Literally: gold / metal – mouth – tree / wood – tongue
Alternately: Someone who leads the people through skillful (spoken) expression. A guide or leader of public opinion. The image is of a metal bell with a wooden clapper, as was apparently used in ancient China as notice of official pronouncements.
Notes: 木 may also be pronounced moku, although this seems to be less common.
This phrase comes to us from the Fayan, (『法言』, Hougen in Japanese) a.k.a. the Model Sayings, a 2000-year-old collection of writings in the form of, let us say, Socratic dialogues, except the Socrates is actually poet Yang Xiong (揚雄, You Yuu).