God willing vs knock on wood

God willing

intj
  • Barring unforeseen circumstances. 

  • Used to indicate acceptance of God's will when expressing an intention or hope. 

knock on wood

intj
  • Hopefully; a self-directive to undertake the customary action to ward off bad luck. 

verb
  • To take a customary action to ward off some misfortune that is believed to be attracted by a presumptuous statement. 

How often have the words God willing and knock on wood occurred in a corpus of books? (source: Google Ngram Viewer )