Source: Book of Exalted Deeds
Sacred power suffuses your unarmed strikes.
Prerequisite: Improved Unarmed Strike, Ki strike (lawful), Cha 15.
Benefit: Your unarmed strikes deal 1 extra point of damage to evil creatures, or 1d4 points to evil outsiders and evil undead. In addition, they are considered good-aligned for purposes of overcoming damage reduction.