Holy Power

Holy Power set the caster's strenght to 18/00, the THACO similar to as a same level fighter has (but the spell doesn't give the fighter's bonus to the attack/round), and plus one hit point per caster level.

In-game description
"Holy Power Through this spell, the caster imbues himself with the strength and skill of a Fighter of the same level. The priest’s Strength is set to 18/00, even if it is normally higher, his THAC0 becomes that of a Fighter of the same level, and he gains 1 temporary hit point for every level he has attained. This will last for the duration of the spell or until successfully dispelled."