believe in vs cling to

believe in

verb
  • To ascribe existence to. 

  • To believe that (something) is right or desirable. 

  • To have confidence in the ability or power of. 

cling to

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

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

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

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