If you would escape moral and physical assassination, do nothing, say nothing, be nothing — court obscurity, for only in oblivion does safety lie.

Elbert Hubbard (1856–1915) American writer, businessman, philosopher

Little Journeys to the Homes of American Statemen, “William H. Seward” (1916)
    (Source)

Variants show up elsewhere in Hubbard's writings and and his quote epigrams.

• To escape criticism -- do nothing, say nothing, be nothing.
• To avoid unkind criticism: do nothing, say nothing, be nothing.
• There is only one way to avoid criticism: do nothing, say nothing and be nothing.

Often misattributed to Aristotle.