C. S. Lewis Quotes about Sacrifice

Letter to Arthur Greeves on December 29, 1935. "They Stand Together: The Letters of C. S. Lewis to Arthur Greeves (1914-1963)". Book by C. S. Lewis, p. 477, 1979.
C. S. Lewis (2013). “The Chronicles of Narnia Complete 7-Book Collection with Bonus Book: Boxen”, p.26, Harper Collins