1
general::
Phrase(s): sum and substance
a summary; the gist. • Can you quickly tell me the sum and substance of your proposal? • In trying to explain the sum and substance of the essay, Thomas failed to mention the middle name of the hero.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
The essence or gist of something, as in The sum and substance of their platform is financial conservatism. This redundant expression?? both sum and substance here mean "essence"has probably survived owing to alliteration. Shakespeare used it in The Two Gentlemen of Verona (4:1): "My riches are these poor habiliments [clothes], Of which if you should here disfurnish me, You take the sum and substance that I have."
American Heritage Idioms