Be true to thine own self

Nunca olvides que sólo te das a ti mismo.

Ante todo, respétate a ti mismo

Hold yourself to your standard.

Lend yourself to others, but give yourself to yourself.

You must be a light unto yourself.

Be a light unto oneself

[E]veryone is orthodox to himself…

Lie to yourself until it's true.

They's times when how you feel got to be kep' to yourself.

Being entirely honest with oneself is a good exercise.

Know that to give to yourself is a part of giving.

Anything you do to and for another person, you do it to and for yourself

If you are alone you belong entirely to yourself. If you are accompanied by even one companion you belong only half to yourself or even less in proportion to the thoughtlessness of his conduct and if you have more than one companion you will fall more deeply into the same plight.