pour oil on troubled waters vs rub it in

pour oil on troubled waters

verb
  • To calm, appease or quieten a person or situation. 

rub it in

verb
  • To add insult to injury; to emphasize one's strengths or another's weaknesses in a manner that degrades another. 

How often have the words pour oil on troubled waters and rub it in occurred in a corpus of books? (source: Google Ngram Viewer )