Nothing incites to money-crimes like great poverty or great wealth.

Mark Twain (1835-1910) American writer [pseud. of Samuel Clemens]

Quoted in Merle Johnson, ed., More Maxims of Mark (1927)
    (Source)

Not found in a primary source. Johnson was a rare book collector who published the first thorough bibliography of Twain's works in 1910. His 1927 work is a 15-page pamphlet, generally considered authentic by scholars, but it provides no other context for the saying.