Eye for an Eye

Eye for an Eye is a common paladin spell card, inducted into the Legacy set, formerly from the Classic set.

Strategy
This is an excellent card to play when your opponent is about to unleash a powerful attack or spell against you. However, keep in mind that multi-hit attacks, such as Arcane Missiles, will only trigger this ability once, causing only one damage to be shot at the enemy hero.

It can be used as a soft tech card against Ice Block. If you can leave the Mage at 1 Health before Ice Block is activated, they will be unable to deal any damage your hero until they can recover some of their Health back.

When playing against this card, test for it by dealing a small amount of damage before committing to a larger attack. For example, playing C'Thun (as well as all other "missiles" effect) can almost negate an opponent's Eye for an Eye, since only the first point damage that C'Thun will deal to the enemy hero will trigger Eye for an Eye and will be dealt back to you, while any subsequent damage that C'Thun will deal to the enemy hero will not be affected by Eye for an Eye.

Eye for an Eye is quite capable of causing the destruction of both heroes in a single turn, resulting in a draw for both players.

Lore
In World of Warcraft, is a talent available to paladins who specialize in. Similar to the spell in Hearthstone, this talent causes enemy magic attacks against the paladin to have a chance of dealing damage back.

Trivia

 * Prior to the changes to Alexstrasza in Patch 1.0.0.4217 and to secrets in Patch 1.0.0.4944, it was possible for the paladin to use the two cards in combination to directly deal 15 damage to the opponent, by directing Alexstrasza's Battlecry at themselves while Eye for an Eye was active. While this still dealt 15 damage to the paladin, the resulting burst damage was formidable, and extremely effective in closing games.
 * The artwork for this card comes from the World of Warcraft Trading Card Game "Blood of Gladiators" series, for the card Thoros the Savior.

Patch changes

 * Moved from Classic to Legacy set.