Draw Upon Holy Might

When this spell is cast, the priest's body shudders and glows with a shimmering aura as it becomes a vessel for the power of his god. As a result, the caster may choose to increase one ability score (only Strength, Dexterity, Constitution, and Charisma are eligible) by +1 per three levels of his experience (+1 at 3rd level, +2 at 6th, etc.).
Only one attribute may be increased. The effect lasts for the duration of the spell. Attributes may be increased above the normal restrictions due to race and class, to a maximum of +6. All benefits for exceptional attributes listed in the Player's Handbook apply; however, the divine abilities found in the Legends & Lore book cannot be gained by use of this spell.
For example, an 18th-level priest with Strength 15 could increase his Strength to 21 for 18 rounds, granting him a +4 attack bonus, a +9 damage adjustment, etc. When the spell ends, the energy abruptly leaves the priest's body, leaving him physically and mentally drained. He is nearly comatose and can do nothing but rest for the next 4d6 turns. A successful Constitution check (at the priest's normal attribute score) reduces this time by 50%.

[Tome of Magic]

Sphere: Summoning
(Invocation)
Level: 2

Range: 0
Components: V, S, M
Duration: 1 round/ level
Casting Time: 2
Area of Effect: The caster
Saving Throw: None

Material Components:
the priest's holy symbol and a vial of holy water that has been blessed by the high priest of the character's faith