Your strike flares with holy radiance, which sears nearby undead.

Encounter   ✦     Divine, Radiant, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. AC

Hit: 3[W] + Strength modifier radiant damage. Each undead creature within 5 squares of you takes radiant damage equal to your Strength modifier and is subject to your divine sanction until the end of your next turn.

Published in Divine Power, page(s) 105.