Aura versus Alignment

Description
When this spell is cast, you choose to be protected from either good or evil. You receive a +4 deflection bonus to Armor Class, immunity to mind-affecting spells and spell-like abilities used by creatures of the chosen alignment, and spell resistance 25 against spells cast by creatures of the chosen alignment. In addition, if Holy Aura is chosen, then the caster's attacks do a 1d6 divine energy damage bonus against evil-aligned creatures, and if Unholy Aura is chosen, then the caster's attacks do a 1d6 negative energy damage bonus against good-aligned creatures.