## shake my head ##

"reject what you are saying" (See: [[rc://en/ta/man/translate/figs-metonymy]])

## Oh, how I would encourage you with my mouth! How the comfort from my lips would lighten your grief! ##

Job's sarcasm is communicating: "By saying to you what you said to me earlier, I would not encourage you or lighten your grief."   (See: [[rc://en/ta/man/translate/figs-euphemism]])