cling to vs hold to

cling to

verb
  • To remain by (someone's) side; to refuse to leave the company of. 

  • To have an intense emotional dependency on (someone). 

  • Used other than figuratively or idiomatically: see cling, to. 

hold to

verb
  • To compel (someone) to remain faithful to (a commitment, moral standard, etc.). 

  • To adhere strongly to (a conviction, story, etc.). 

  • To share or subscribe to (a belief, etc.). 

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