Analysis of I Saw a Chapel

I saw a chapel all of gold
     That none did dare to enter in,
     And many weeping stood without,
     Weeping, mourning, worshipping.

I saw a serpent rise between
     The white pillars of the door,
     And he forc'd and forc'd and forc'd,
     Down the golden hinges tore.

And along the pavement sweet,
   Set with pearls and rubies bright,
   All his slimy length he drew
   Till upon the altar white

Vomiting his poison out
   On the bread and on the wine.
   So I turn'd into a sty
   And laid me down among the swine.