The panther change of the junzi

A few months ago someone asked me what the panther change in the sixth line of hexagram 49 might refer to. This is what I answered him:

It seems to be an age old fixed expression, and to find out what it refers to we have to look at the context. The Yi says

君子豹變.小人革面.

There is rhyme in these two sentences: Jūnzǐ bàobiàn. Xiǎorén gémiàn, and they obviously belong to each other like yin & yang. "The junzi changes like a panther. The small person changes his face." What the small person does is (more or less) bad, what the junzi does is good. Baobian, a panther/leopard change, seems to be good. The Hanyu Da Cidian says about 豹變:

1. 謂如豹文那樣發生顯著的變化。幼豹長大退毛，然後疏朗煥散，其毛光澤有文采。
   Said when the markings on a leopard distinctively change. When a young leopard grows up he depilates, after that shiny [spots] appear and his fur gets glossy with rich and bright colors.
2. 喻人的行為變好或勢位顯貴。
   A metaphor used when a person reforms his action or obtains an eminent place of power.

Baobian is an improvement for the better. Gemian 革面 however, is not:

1. 謂改變臉色或態度
   Said when one changes his facial expression or attitude.
2. 比喻徹底悔改
   Metaphor for thorough repent and reform (But this is a relatively young meaning of gemian, only used since the Jin Dynasty HM)
3. 用皮革做的面子
   Name for the outside of leather.

I think that in the Yi the first meaning is meant. Baobian is a transformation which takes place in one's nature, it cannot be controlled, it has to take it's natural course. Gemian is a change only in the face, the outside expression which can be controlled by ones will and intentions. Follow nature is good, follow the will is not good. Therefore 征凶.居貞吉. A (planned, will-driven) journey would not do any good. Stay put and perform the divination at one's own place (that is where nature is) is good.