Go cautiously where you suspect depth. Sagacity goes cautiously forward while discretion covers the ground. Nowadays there are unsuspected depths in human intercourse, you must therefore plumb the waters as you go.
Much that well may be thought cannot wisely be said.
Know when to speak – for many times it brings danger, to give the best advice to kings.
Discretion is the better part of valour.
There are no two people on this earth who could not be turned into deadly enemies by a devilishly contrived indiscretion.
Mention not a rope in the house of one whose father was hanged.
Who never walks save where he sees men’s tracks, makes no discoveries.
Those who live in glass houses should not throw stones.
Perish discretion when it interferes with duty.
He that hears much, and speaks not all, shall be welcome both in bower and hall.