Revenge, at first though sweet, Bitter ere long back on itself recoils.

I sung of Chaos and Eternal Night, Taught by the heav'nly Muse to venture down The dark descent, and up to reascend.

To be weak is miserable, Doing or suffering.

You can make hell out of heaven and heaven out of hell. It's all in the mind.

Or sweetest Shakespeare, Fancy's child!

Vain wisdom all, and false philosophy.

A good principle not rightly understood may prove as hurtful as a bad.