Spirit Bind

When cast near the corpse of a newly dead individual, this spell binds an individual's life force to its physical remains, preventing a spirit's departure to the afterlife. The (presumably unwilling) spirit of the deceased is entitled to a saving throw vs. spells to resist the effect (made as if still alive), modified by a -1 penalty for every three levels of experience past the 1st of the priest (-2 penalty at 7th level, -3 at 10th level, to a maximum of -6 at 19th level).
Spirit bind must be cast on the body of the deceased within one round of the individuals' death for every level of experience of the caster. Thus a 10th-level priest may bind the spirit of an individual who was dead for up to a turn. If successful, the spirit bound corpse takes on a pale silvery or mauve radiance. Normal animals and even monsters of low intelligence will involuntarily shun this necromantic aura.
While under the effect of this spell, a cadaver becomes immune to the normal effects of rot and decay. Spirit bind may thus be employed to preserve a body for a subsequent raising or resurrection, for which the spirit bound individual is considered to have been dead for less than a day. Furthermore, because of the strong, necromantic link already forged between the spirit and the body, the victim receives a -10% bonus on his or her system shock roll.
However, this spell is more often put to much darker ends by death priests. Note that, for the deceased, being spirit bound is not a pleasant experience. The spirit may not be aware of its current location or the passage of time (or so good-aligned priests who employ this spell may like to think), but it is most certainly aware of being trapped or constrained. Once bound to its body, a spirit is much easier to coerce with threats of permanent imprisonment and to interrogate with Speak With Dead spells. Some sages speculate spirit bind may be also involved in the loathsome creation of a flesh golem.
While immune to normal decay and dissolution (and the ravaging of animals and dumb monsters), the spirit bound corpse is in no way protected from destruction by a sentient creature or individual. Should its body be destroyed, the spirit instead becomes bound to the last area resided by the physical remains. Such a restless, quasi-liberated spirit might become a non-corporeal undead (such as an apparition, banshee, haunt, poltergeist, wraith, ghost, or spectre). A spirit imprisoned in this manner may only be released by casting the reverse of this spell (see below) or Dispel Evil (dispel magic and remove curse are ineffective). Because of the considerable dangers for the subject and moral quandaries involved, good-aligned priests are naturally reluctant to employ spirit bind except in the most dire emergencies.

Reverse: Spirit Release

The reverse of this spell, spirit release, severs a spirit's ties with the material world and is a common practice at formal funerals. Unwilling, non-corporeal undead are entitled to a saving throw to resist the spell's effects, subject to the same penalties as outlined for spirit bind. If failed, the undead spirit departs for the outer planes and is effectively dispersed. Note that neither version of this spell affects corporeal undead (such as ghouls, liches, and vampires), nor do they affect extraplanar creatures.

[Complete Book of Necromancers]

Reversible

Sphere: Necromantic
(Necromancy)
Level: 3

Range: 10 yards
Components: V, S, M
Duration: Permanent
Casting Time: 1 round
Area of Effect: One corpse
Saving Throw: Negates

Material Components:
the priest's holy/unholy symbol and a recently deceased corpse