John Donne's "The Flea"

This poem was not at all what I expected, because it combined two things that, to me, had only a slight connection, if that. In class, we discussed how the flea was Christ-like (which seems odd in and of itself). However, the flea is also a symbol of the sexual desires the narrator has, for the flea gets to walk on the body of the narrator's mistress, and even suck her blood. While this is a pretty disturbing image, I think that the poem is actually quite humorous. Whoever thought that a flea could be a symbol of someone's love?
As for the religious aspect, there is significant evidence that supports a religious reading for the poem, no matter how inconsistent it may seem within the context of the poem. For example, when the narrator talks about the trinity of the flea, exclaiming “Oh stay, three lives in one flea spare. ” This reference to the Trinity is strengthened by another line later on in the poem, “Purpled thy nails, in blood of innocence.” Purple has long been a symbol of Christ's kingdom, and the "nails" and "blood of innocence" is a clear reference to the Crucifixion.