Magical Vestment

This spell enchants the caster's vestment, providing protection equivalent to armor. 

It will only function while the cleric is on ground consecrated to his or her deity (cf. 1st-level ceremony spell). If any armor or protective device is worn during the spell duration, the vestment protects as if normal chain mail armor. If no other protection is worn, the vestment also gains a +1 enchantment for each four levels of the cleric, to a maximum effect of chain mail +4 (base AC 1). 

The magic lasts for 6 rounds per level of the caster, or until the caster loses consciousness or leaves the consecrated area.

The material components are the vestment to be enchanted and the cleric's holy/unholy symbol.