Source: Book of Exalted Deeds
Sacred power suffuses your attacks with a certain kind of weapon.
Prerequisite: Cha 15, Weapon Focus with the specified weapon.
Benefit: Whenever you wield a specific kind of weapon, it deals 1 extra point of damage to evil creatures, or 1d4 points to evil outsiders and evil undead. In addition, that weapon is considered good-aligned for purposes of overcoming damage reduction.
Special: You can take this feat more than once, selecting a different weapon each time.