Retribution is a second-level Life magic spell from Heroes of Might and Magic IV. It costs three mana and is cast on a friendly target. When the enemy attacks the target in melee combat, the attacker will take damage based on the level of the caster.
Pain will be visited upon those who strike me. A holy and righteous pain!
Not as useful as it might appear, this spell never really does enough reatliatory damage to be worthwhile. It can be useful, though, if you're attacking with a lone hero. Casting this spell means you can do a decent amount of damage to attacking stacks while you concentrate on keeping your hero alive with healing spells. A tactic for the patient spellcaster with lots of spell points.
Retribution + Regeneration = A lone hero facing, and possibly defeating, an army.