Hamlet

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.

– Hamlet, Act I, sc. iii

(source 1) (source 2)

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.

– Shakespeare’s Hamlet, Act I, sc. iii