TO ARTHUR GREEVES: On the seven deadly sins.
10 February 1930
When I said that your besetting sin was Indolence and mine Pride I was thinking of the old classification of the seven deadly sins: They are Gula (Gluttony), Luxuria (Unchastity), Accidia (Indolence), Ira (Anger), Superbia (Pride), Invidia (Envy), Avaritia (Avarice). Accidia, which is sometimes called Tristitia (despondence) is the kind of indolence which comes from indifference to the good—the mood in which though it tries to play on us we have no string to respond. Pride, on the other hand, is the mother of all sins, and the original sin of Lucifer—so you are rather better off than I am. You at your worst are an instrument unstrung: I am an instrument strung but preferring to play itself because it thinks it knows the tune better than the Musician.
From The Collected Letters of C.S. Lewis, Volume I
Compiled in Yours, Jack