didactic vs exhorting

didactic

adj
  • Instructive or intended to teach or demonstrate, especially with regard to morality. 

  • Excessively moralizing. 

  • Teaching from textbooks rather than laboratory demonstration and clinical application. 

exhorting

noun
  • exhortation 

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