Hopkins was born in 1844, the first of nine children of a High Anglican couple. A bright schoolboy, he obtained a scholarship to Balliol College, Oxford, where he became the star scholar in classical studies. Coming under the influence of John Henry Newman, famous Oxford convert to Catholicism 20 years earlier, he became Catholic one year before leaving Oxford, and at the age of 23 entered the Society of Jesus. In the course of his studies he came across the theology and philosophy of Duns Scotus which revived his interest in writing, and there rose up from within him a wholly personal vision of unchanging nature and English poetry. In 1877 he was ordained priest and did parish work in England. In 1884 he was moved to Dublin, where in 1889 he died of typhus, saying, "I am so happy".
Therefore Hopkins' life was wholly framed within the 19th century, hey-day of English Liberalism and Romanticism. However, that within him which made him convert to Catholicism and become a priest made his Romanticism quite different from that of his contemporaries, who could mostly hear only "the melancholy, long, withdrawing roar" of faith, of God, of hope. "God's Grandeur" is full of God, and full of hope.
Cast in classic sonnet form, the poem's first four lines tell of God's greatness flashing and oozing forth from all Creation. Then how (line 4) can modern man be paying him so little attention ? The answer (l.5-8) is that centuries of living for money ("trade") have cut man off from nature ("nor can foot feel"), and stripped both man and nature ("soil is bare") of God. Yet (l.9-14) God is still there, deep within natural things, as ever. Man may be putting out the lights of Western civilisation, still God is constantly recreating the world with brightness and warmth.
On a first reading, the originality of Hopkins' language and imagery may be off-putting. Who ever heard for instance of the Lord God being compared to tin-foil or to oil ? But inside Hopkins is a new wine which will not go into old bottles. To punch over the lifelessness of modern man he resorts to repetitions ("trod...trod...trod": "seared... bleared...smeared"), and in 12 of the 14 lines he uses old-fashioned alliterations ("smudge,smell","foot, feel",etc.).
As for the rhythm, instead of the classic English iambic pentameter (te-tum,te-tum,te-tum,te-tum,te-tum), we have a variety of feet and a varying number of beats to a line, from three (L9,13), to five (l.10), mostly four (eg l.1).
However, let nobody think Hopkins is indisciplined. He has chosen the Petrarchan sonnet form which allows of only four different rhymes for the 14 lines (here: --od, --oil, --ent and --ings), which for an English poet is quite demanding. And notice how carefully crafted is the last line of the sonnet, its climax:-- "World broods" matches "warm breast" and balances "bright wings" (wb, wb, bw), while the spondees (tum, tum) "World broods" and "bright wings" at each end frame two anapaests (te-te-tum) "with warm breast" and "and with ah!". Read the line slowly aloud, and see if you do not get a kick out of Fr. Hopkins!
Clearly he has no interest in being original for its own sake. Rather from within the liberal 19th century, decadent and growing tired, the convert-priest has a fresh vision of Creation and its Creator which calls for fresh language and rhythms. In truth, whoever recovers God will recover originality!
Could weary men but once more find their way
To God, how light and fresh would dawn the day!