But thou, contracted to thine own bright eyes, Feed'st thy light's flame with self-substantial fuel, Making a famine where abundance lies, Thyself thy foe, to thy sweet self too cruel.
Nor stony tower, nor walls of beaten brass,
Nor airless dungeon, nor strong links of iron,
Can be retentive to the strength of spirit;
But life, being weary of these worldly bars,
Never lacks power to dismiss itself.