 Those in the deeper vitals rage:
Lo, Poverty, to fill the band,
That numbs the soul with icy hand,
  And slow-consuming Age.
To each his suff'rings: all are men,
Condemn'd alike to groan,
The tender for another's pain;
 Th' unfeeling for his own.
Yet ah! why should they know their fate?
Since sorrow never comes too late,
  And happiness too swiftly flies.
Thought would destroy their paradise.
No more; where ignorance is bliss,
  'Tis folly to be wise.
Gray’s closing lines spawned the extremely well-known phrase “Ignorance is bliss”. He means something quite different to the carefree, hedonistic philosophy it has acquired, though. The lines represent the speaker (who is pretty well Thomas Gray) pining for his youth when ignorance wasn’t so frowned upon, and wisdom wasn’t so revered, or even important.
Ode on a Distant Prospect of Eton College