You cannot run from the divine hand of justice.
Hammer of Wrath is a level 46 paladin ability. It is a Holydirect damagepaladin spell that flings a hammer crackling with Holy power at a wounded enemy, but can only be used when the target is at or below 20% health, or during [Avenging Wrath].
Hammer of Wrath is a fast and powerful attack, the main constraint of which is that it can only be used on enemies at or below 20% health. Its large burst of instant damage makes it an excellent execute.
Nothing is as devastating as running away with a few hundred health only to be tagged with a paladin's Hammer from long range. Paladins may make full use of the Hammer on fleeing targets, as well as mobs and bosses who are in their death throes.
There is no minimum range on the Hammer; it can be used at point-blank distance.
The attack is resolved as a ranged special-attack that does non-physical damage, similar to a Hunter's [Arcane Shot]. It can miss, it can be blocked (if the target is facing you), it can be dodged, and it does double damage on a crit.
The Retribution Tier 8 Paladin Armor Set Conqueror's Aegis Battlegear (level 80) includes a 2-piece set ability that increases the damage dealt by your Exorcism and Hammer of Wrath ability by 10%.
The Retribution-centric Tier 6 Paladin Armor Set Lightbringer Battlegear (level 70) includes a 4-piece set ability that increases the damage dealt by your Hammer of Wrath ability by 10%.
Hammer of Wrath is a basic Paladin spell in Hearthstone. The flavor text reads: "A good paladin has many tools. Hammer of Wrath, Pliers of Vengeance, Hacksaw of Justice, etc."
Patches and hotfixes
Patch 9.0.1(2020-10-13): changed to a baseline ability, now available to all specs.
Patch 8.0.1(2018-07-17): Re-added as Retribution talent. Now deals damage based on attack power instead of spell power, and no longer generates a charge of Holy Power.
Patch 3.0.3(2008-11-04): Now can't be used until the target is below 20% health.
Tooltip has not been updated accordingly.
Patch 3.0.2(2008-10-14): Hammer of Wrath is now considered a Retribution spell, moved from Holy, mana cost reduced, now instant cast, global cooldown increased to 1.5, missile speed increased, now usable on targets below 35% health and now scales with attack power and spell power.
Patch 2.3.0(2007-11-13): Hammer of Wrath mana cost reduced.
Patch 2.2.0(2007-09-25): Hammer of Wrath cast time reduced to .5 seconds, global cooldown reduced to .5 seconds.
Patch 2.1.0(2007-05-22): Hammer of Wrath: Rank 4, damage increased.