Never esteem anything as of advantage to you that will make you break your word or lose your self-respect.
Look well into thyself; there is a source of strength which will always spring up if thou wilt always look there.
If you are distressed by anything external, the pain is not due to the thing itself, but to your estimate of it; and this you have the power to revoke at any moment.
Never let the future disturb you. You will meet it, if you have to, with the same weapons of reason which today arm you against the present.