Milton was a master of both short and longform poetry. Obviously, he's best known for Paradise Lost, as well as other longer works like Paradise Regained, Samson Agonistes, and the elegy Lycidas.

But he was also a master of the sonnet, and there may be no more famous one by him (and certainly no more famous a pair of closing lines) than in this poem. Milton's blindness was a tragedy, almost certainly depriving the world of even more great works by the greatest English writer of his day. While he unquestionably (and understandably) felt anger over what happened to him (I've read a couple of bios of him), his aim was always something more accepting (and definitely more accepting than I think I could ever be).

Sonnet 19: When I consider how my light is spent by John Milton

When I consider how my light is spent,   Ere half my days, in this dark world and wide,   And that one Talent which is death to hide   Lodged with me useless, though my Soul more bent To serve therewith my Maker, and present   My true account, lest he returning chide;   “Doth God exact day-labour, light denied?”   I fondly ask. But patience, to prevent That murmur, soon replies, “God doth not need   Either man’s work or his own gifts; who best   Bear his mild yoke, they serve him best. His state Is Kingly. Thousands at his bidding speed   And post o’er Land and Ocean without rest:   They also serve who only stand and wait.”