call to arms vs call together

call to arms

noun
  • An appeal to fight or to engage in conflict. 

  • An appeal to undertake a particular course of action or to support a specific cause; a call to action. 

call together

verb
  • To request that (certain people) assemble; to gather (certain people) for a meeting. 

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