encourage vs stir up

encourage

verb
  • To mentally support; to motivate, give courage, hope or spirit. 

  • To spur on, strongly recommend. 

  • To foster, give help or patronage 

stir up

verb
  • To arouse or excite (passion or action). 

  • To move or disturb slightly; to make turbid. 

  • To mix (ingredients) by stirring. 

How often have the words encourage and stir up occurred in a corpus of books? (source: Google Ngram Viewer )