his above all: to thine own self be true - Shakespeare Hamlet quote

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.

– William Shakespeare

Hamlet, Act 1, Scene 3. Before Laertes leaves for Paris, his father Pononius imparts these words of advice on leading a good and balanced life.