Marks Of Forbiddance

Abjuration [mind-affecting]
Level: Paladin * 3
Components: V, S
Casting Time: 1 Standard Action
Range: close (25 ft. + 5 ft./2 levels)
Target: one enemy and one ally
Duration: 1 round/level
Saving Throw: Will negates, see text
Spell Resistance: yes
  Marks of Forbiddance magically brand two creatures, preventing them from committing violence against one another. When you cast this spell choose one enemy and one ally within range. Both targets become branded with the sigil of forbiddance. Until the end of the spell's duration, in order for the two targets to attack one another, even with a targeted spell, each attacker must attempt a Will Save. If the save succeeds, that target can attack the other normally.
  If the save fails, the target can't follow through with the attack and the action is lost. This spell does not prevent the targets from attacking each other with area of effect spells or abilities.