purify vs sully

purify

verb
  • To cleanse, or rid of impurities. 

  • To become pure. 

  • To free from guilt or sin. 

sully

verb
  • To become soiled or tarnished. 

  • To corrupt or damage. 

  • To soil or stain; to dirty. 

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