covenant vs oath

covenant

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. 

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

  • To enter a formal agreement. 

  • To make a stipulation. 

  • To bind oneself in contract. 

oath

noun
  • A solemn pledge or promise that invokes a deity, a ruler, or another entity (not necessarily present) to attest the truth of a statement or sincerity of one's desire to fulfill a contract or promise. 

  • A light, irreverent or insulting appeal to a deity or other entity. 

  • A curse, a curse word. 

  • A statement or promise which is strengthened (affirmed) by such a pledge. 

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