Fortify

This is a simple cooperative magic spell. Only one priest can cast the spell, but like Mystic Transfer, another priest is required for the spell to have any effect. Through this spell, the priest improves the quality of another priest's healing spells.
For the fortify spell to work, it must be cast simultaneously with a Cure Light Wounds, Cure Serious Wounds, or Cure Critical Wounds. The priest casting fortify must lay his hand on the priest attempting the cure. When both spells are cast, additional energy flows through the second priest and into the creature being healed. Fortify automatically causes the cure spell to function at maximum effect. Thus, a cure serious wounds would automatically heal 17 points of damage and a cure critical wounds would heal 27 points of damage.

[Tome of Magic]

Sphere: Healing
(Necromancy)
Level: 4
Cooperative

Range: 0
Components: V, S, M
Duration: Special
Casting Time: 6
Area of Effect: Creature touched
Saving Throw: None

Material Components:
the priest's holy symbol