Or "Holy Sonnet 14"
It is a very physical poem; I read it as about the poet's body more than about the poet's mind/heart/soul. The imagery of the poem can be fit into three distinct parts.
"Batter my heart, three-personed God; for, you
As yet but knock, breathe, shine, seek to mend;
That I may rise, and stand, o'erthrow me, and bend
Your force, to break, blow, burn, and make me new."
Here is the violent imagery: the poet is asking God to forcibly enter him. It is in these four stanzas that we get so many strong action verbs: batter, knock, breathe, shine, seek, rise, stand, o'erthrow, bend, break, blow, burn, make. Direct, powerful language. Even choppy to connote the power and violence ("break, blow, burn").
"I, like an usurped town, to another due,
Labour to admit you, but oh, to no end,
Reason your viceroy in me, me should defend,
But is captivated, and proves weak or untrue,"
Here is the weakest part of the poem, right in the heart: the metaphor of the poet as a besieged city working to let God in. It fits thematically (and the image is consistent with the first part), but it is not as strong as the first and last parts of the poem.
"Yet dearly'I love you, and would be loved fain,
But am betrothed unto your enemy,
Divorce me, untie, or break that knot again,
Take me to you, imprison me, for I
Except you enthrall me, never shall be free,
Nor ever chaste, except you ravish me."
The imagery shifts to marriage and sex. The poet is married to the devil, and wishes for God to "divorce" him from the devil in order to take him for himself. We end with paradox: to be free from sin, God must forcibly enter the poet (a metaphor for grace: humans are helpless without it), and to be chaste, God must "ravish" him. Metaphysical poets seemed untroubled using sexual imagery when describing their relationship with God.
Why is "imprison" me in the love/marriage metaphor rather than the broader violence metaphor or the seige metaphor? Perhaps it simply brings unity to the sections of the poem. We might also look at Donne's "Confined Love," where the poet suggests laws of marriage were caused by patriarchy and confine true love (real love needs to spread itself around). To be married to the devil, then, is to be imprisoned; if God marries (or "imprisons") the poet, he is paradoxically made free.
Donne is a masterful poet for his ability to use physical language to describe what is a spiritual experience. It is not abstract--Donne makes this a poem about "action." The imagery isn't based on nouns, but on verbs; reading this poem, we know something is happening.