Several Arena Rewards armor sets for the Paladin class include a 4 piece set bonus that reduces the cooldown of Hammer of Justice by a further 10 seconds. This bonus is also found on Crusader's Scaled Battlegear and Crusader's Ornamented Battlegear, two superior-quality PvP sets sold by various factions in Outland.
Tips and tricks
Useful to allow you to heal without interruption or to flee. This stun is one of the most flexible in the game, as it will not break due to damage or other spells being cast on the target, nor does it cause any amount of threat when used.
It cannot be used on a target that already has a Hammer of Justice stun active.
Most bosses and some high-level mobs are immune to Hammer of Justice.
Hotfix (2012-10-04):Both Repentance and Hammer of Justice can now be applied to the same target.
Patch 4.0.1 (2010-10-12): No longer interrupts non-player spellcasting.
Patch 3.2.0 (2009-08-04): Tooltip now specifies that the Interrupt effect only occurs on non-player targets.
Hotfix (2009-06-08):When immune to the stun of following abilities, [Maim], [Bash], and Hammer of Justice will no longer cause player spells to be interrupted but they will still interrupt NPCs. Also, when these abilities do stun a player target, they will not perform an interrupt effect and lock out the affected magic school. As an example, if a Mage is channeling Arcane Missiles and is hit by Hammer of Justice, Blink will now be available as the Arcane school will not be locked out as it was before.
[Fist of Justice], 
[Jurisdiction]
Hotfix (2012-10-04): Both Repentance and Hammer of Justice can now be applied to the same target. 
