Percy Bysshe Shelley Quote

Gentleness, Virtue, Wisdom, and Endurance,
These are the seals of that most firm assurance
Which bars the pit over Destruction's strength;
And if, with infirm hand, Eternity,
Mother of many acts and hours, should free
The serpent that would clasp her with his length;
These are the spells by which to reassume
An empire o'er the disentangled doom.

Demogorgon, Act IV, l. 562–569. - Prometheus Unbound (1818–1819; publ. 1820)