Your zeal on the battlefield allows you to deal extra damage in combat.
Prerequisites: Ability to cast 4th-level spells, access to the War domain.
Benefit: As long as you have a 4th-level or higher War domain spell available to cast, you gain a bonus on your weapon damage rolls equal to the level of the highest-level War spell you have available to cast.
As a secondary benefit, you gain a +1 competence bonus to your caster level when casting force spells.
Source: Complete Champion, page 60.