ever vs for eternity

ever

det
  • Shortening of every 

adv
  • As intensifier following an interrogative word. 

  • In any way. 

  • Continuously, constantly, all the time (for the complete duration). 

  • At any time. 

  • Always, frequently, forever. 

adj
  • Occurring at any time, occurring even but once during a timespan. 

for eternity

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