When the level cap was 14, and we got this spell avaiable, there was no tech to mirror what the PnP spell does. Now, we have a entire class that works on the basis of item property imbuing (Artificer), and some code could be borrowed for this spell to remain useful to the endgame.
Holy Sword: This spell adds holy burst to weapons and shields the caster is wearing, and they will bypass good, silver, magic, cold iron, and byeshk damage reduction. The wielder will have a static protection from evil effect while holding an enchanted weapon. While this enchantment is active, the weapon will be temporarily bound to character. These effects will last for 1 minute per caster level.
(New text description by ZeebaNeighba, on post #18)
This would works like Insightful Strikes/Damage, IE: stacks with Deadly/Elemental Weapon.