The speaker begins by stating how little that which his lover denied him is as small as the title creature, and notices how the mingling of their blood within the title creature "Our marriage bed, and marriage temple is".  
The speaker comments how he and his lover are "cloysterd in these living walls of Jet", and goes on to state that the death of the title character would mean "sacrilege, three sinnes in killing three."  The speaker begins by stating how little that which his lover denied him is as small as the title creature, and notices how the mingling of their blood within the title creature "Our marriage bed, and marriage temple is".  In the third stanza, the speaker's lover, "Cruell and sodaine", purples her "naile, in blood of innocence" by killing the title creature.  FTP, identify this poem about an insect by John Donne.
The speaker comments how he and his lover are "cloysterd in these living walls of Jet", and goes on to state that the death of the title character would mean "sacrilege, three sinnes in killing three."  
The Flea