Weary with toil, I haste me to my bed, The dear repose for limbs with travail tired; But then begins a journey in my head To work my mind, when body’s work’s expired: For then my thoughts, from far where I abide, Intend a zealous pilgrimage to thee, And keep my drooping eyelids open wide, Looking on darkness which the blind do see; Save that my soul’s imaginary sight Presents thy shadow to my sightless view, Which like a jewel hung in ghastly night Makes black night beauteous, and her old face new: Lo, thus, by day my limbs, by night my mind, For thee, and for myself, no quiet find.

[2] In Sonnet 27 the weary poet cannot find rest — not day or night.

As soon as he lies down, another journey begins in his thoughts ("To work my mind") — the destination is the young man, who is far from where the poet is ("from far where I abide").

The poet's thoughts take that journey, and though he sees nothing but the darkness of night, his imagination presents to him an image of the young man, an image that seems to hang before him in the dark, like a jewel.

It follows the rhyme scheme ABAB CDCD EFEF GG, and is written in iambic pentameter, a metre in which each line has five feet, and each foot has two syllables accented weak/strong.