admonition

admonition \ad-muh-NISH-uhn\, noun:

1. Gentle or friendly reproof.
2. Counseling against a fault or oversight; friendly caution or warning.

After debating whether Keayne should be excommunicated, the congregation concluded that an admonition would suffice.
-- Patricia O'Toole, Money & Morals in America

And in religious families, the biblical admonition, "Let he who is without sin cast the first stone," is part of living-room and kitchen table conversations.
-- Ann O'Hanlon, "Strange lessons for inquiring children", Irish Times, September 14, 1998

Or there is this simple admonition: "Be careful, God is watching."
-- Roger Cohen, "A Land Where God Is Working Overtime", New York Times, August 23, 1998

Admonition derives from Latin admonitio, admonition-, from admonitus, past participle of admonere, to remind, or warn, strongly, from ad- (here used intensively) + monere, to remind, to warn.