George Bernard Shaw
Answering each of the clues A through N, and replacing the number and letter combinations of the individual answers with the correct letter will solve this acrostic.  Working backward, placed letters might reveal patterns that suggest words that can then be used as clues to unknown answers of A through N, thereby completing the puzzle.

The answers A through N are:
A, Truant; B, Wyoming; C, Dryad; D, Gluttony; E, Isaac Newton; F, Befuddle; G, Thrush; H, Danube; I, Troy; J, Bohemian; K, Gorgon; L, Twinkle; M, Tally; N, Goldenrod.

The revealed quotation reads:  “You don’t learn to hold your own in the world by standing on guard, but by attacking and getting well-hammered yourself.”

This quote is from the play Getting Married by Irish playwright, George Bernard Shaw.