be friends vs get on

be friends

get on

verb
  • To handle, cope or manage (over time); to perform or make progress. 

  • To board or mount (something), especially a vehicle. 

  • To become late. 

  • To have a good relationship; to get along. 

  • To commence (an action). 

  • To become old. 

  • To progress (with). 

intj
  • Expresses surprise or disbelief. 

How often have the words be friends and get on occurred in a corpus of books? (source: Google Ngram Viewer )