The bit about God killing the villain is a warning against Deus ex machina, which basically means you can’t have some coincidence or “outside agency” killing the bad guy (or solving the major plot problem). It has to be the hero, in some form or fashion, doing the work and “earning” the victory.]
Seems like Lucas and Spielberg went against this advice full force in “Raiders of the Lost Ark” which, otherwise, stayed true to its Pulp and Serial roots. How would the movie have been different if Indiana Jones would have used some skill (or the Ark itself) to defeat the Nazis?