Note:  If you wish, you may read my article Cunning Elements: Water, Fire, and Sacramental Poetics in Donne's I am a little world.

17th-century writers often explore the idea that each individual human being is a microcosm, a little world or mini cosmos that mirrors on a small scale the balanced structure of the macrocosm (the physical universe).  In the macrocosm, chaos is prevented by the orderly division of the elements (earth, air, fire, water): storms and natural disasters result when the elements are thrown out of balance.  In the microcosm of the human body, if all four humors (black bile, blood, yellow bile, and phlegm) are in balance with one another, the body, mind, and emotions are healthy; but if one humor predominates, the imbalance can be problematic. A disproportionate amount of choler makes one "choleric"--easily angered, rash, bold, excitable; too much phlegm makes one "phlegmatic"--lazy, flaccid, unmotivated and cowardly; a predominance of blood makes one "sanguine" (from the French "sang," blood)--extremely cheerful, irrepressible, optimistic. But the most often-discussed imbalance, classified by Renaissance thinkers as a disease, was the excess of black bile, which makes one melancholic"-- overly analytical, pensive, morbid, and sorrowful.  

Note that Donne's Holy Sonnets take Petrarchan love sonnets as their point of dparture.  Review Study Guide 1.

Note also that Donne's Holy Sonnets depend upon the reader's familiarity with a number of Christian doctrines concerning salvation and damnation, faith and works, etc.  But Donne does not simply invoke these doctrines; he explores them.

       Trust not the treason of those smyling lookes,
       Untill ye have thyr guylfull traynes well tryde:
       For they are lyke but unto golden hookes,
       That from the foolish fish thyer bayts doe hyde:
       So she with flattring smyles weake harts doth guyde
       Unto her love, and tempte to theyr decay,
       Whome being caught she kills with cruell pryde,
       And feeds at pleasure on the wretched pray:
       Yet even whylst her bloody hands them slay,
       Her eyes looke lovely and upon them smyle:
       That they take pleasure in her cruell play,
       And dying doe them selves of payne beguyle.
       O mighty charm which makes men love theyr bane,
       And thinck they dy with pleasure, live with payne.