Delay Death

You gesture toward your ally and call upon the power of your beliefs. A soft, golden glow appears on your companion’s chest, around his heart.

(Spell Compendium, p. 63)  
Originally posted on D&D tools

Necromancy

Level: Cleric 4,
Components: V, S, DF,
Casting Time: 1 immediate action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One creature
Duration: 1 round/level
Saving Throw: Will negates (harmless)
Spell Resistance: Yes (harmless)

The subject of this powerful spell is unable to die from hit point damage. While under the protection of this spell, the normal limit of -9 hit points before a character dies is extended without limit. A condition or spell that destroys enough of the subject’s body so as to not allow raise dead to work, such as a disintegrate effect, still kills the creature, as does death brought about by ability score damage, level drain, or a death effect.

The spell does not prevent the subject from entering the dying state by dropping to -1 hit points. It merely prevents death as a result of hit point loss.

If the subject has fewer than -9 hit points when the spell’s duration expires, it dies instantly.