covenant vs vow

covenant

verb
  • To enter into, or promise something by, a covenant. 

  • To enter a formal agreement. 

  • To make a stipulation. 

  • To bind oneself in contract. 

noun
  • A promise, incidental to a deed or contract, either express or implied. 

  • An incidental clause in an agreement. 

  • An agreement to do or not do a particular thing. 

  • A pact or binding agreement between two or more parties. 

vow

verb
  • To make a vow regarding (something). 

  • To declare publicly that one has made a vow, usually to show one's determination or to announce an act of retaliation. 

  • To make a vow; to promise. 

noun
  • A solemn promise to perform some act, or behave in a specified manner, especially a promise to live and act in accordance with the rules of a religious order. 

  • A declaration or assertion. 

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