MILTON! thou shouldst be living at this hour:
England hath need of thee: she is a fen
Of stagnant waters: altar, sword, and pen,
Fireside, the heroic wealth of hall and bower,
The narrator is expressing his wish for  John Milton , English poet & writer of  Paradise Lost , to be alive in the present time. Wordsworth had an enormous respect for Milton’s poetic achievements, and in many ways saw himself as his successor: his epic,  The Prelude , begins with a reference to one of the most famous concluding lines of  Paradise Lost : 

London 1802