In quot. 1600-1 soul of wit should be understood as ‘essence of wisdom’; wit is now commonly understood in its modern sense, the ‘(power of giving sudden intellectual pleasure by) the unexpected, quick, and humorous combining or contrasting of ideas or expressions’ (COD).
Since brevity is the soul of wit‥I will be brief.
[1600-1 Shakespeare Hamlet ii. ii. 90]
Brevity is the soul of wit,—ahem.
[1833 M. Scott Tom Cringle's Log II. v.]
I will not repeat myself, since brevity is the soul of wit.
[1946 D. Welch Maiden Voyage x.]
Clinton is Southern and given to garrulousness while brevity, as they say, is the soul of wit.
[1996 Washington Post 8 Sept. C5]
Related to: brevity and long-windedness
Bibliography of major proverb collections and works cited from modern editions is available here.
