In Act 1, scene 3 of William Shakespeare’s tragedy, Hamlet, the king’s counselor, Polonius, advises his son, Laertes, and his daughter, Ophelia, on issues of virtue and wisdom. Polonius recommends introspection and truthful self-assessment as the basis for honesty with others.
This above all: to thine own self be true,
And it must follow, as the night the day,
Thou canst not then be false to any man.