blessing vs oath

blessing

noun
  • Some kind of divine or supernatural aid, or reward. 

  • A pronouncement invoking divine aid. 

  • Good fortune. 

  • A modern pagan ceremony. 

  • The act of declaring or bestowing favor; approval. 

  • A group of unicorns. 

  • A prayer before a meal; grace. 

  • Something someone is glad of. 

oath

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

  • A curse, a curse word. 

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

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