True Believer

(Magic Item Compendium, page 222, DnD 3.5)

[General]

Your deity rewards your unquestioning faith and devotion.

Prerequisite

Must Choose a single deity to worship, Must be within 1 step of that deities alignment

Benefit

Once per day when you are about to attempt a saving throw you can declare that you are using this feat to gain a +2 on the roll. This feat also allows you to use a relic of the diety you worship without sacrificing a spell slot.