Change the Health of ALL minions to 1.
We are all special unique snowflakes... with 1 Health.
How to get
Equality should be saved for when the drawback of having the health of all your minions set to 1 is outweighed by the benefit of doing the same to your opponent. It is most commonly used as a combo with Consecration, which will wipe out all of the opponent's minions. Equality also works well with Avenging Wrath and Sword of Justice, where a single point of damage is all that is needed. Playing the neutral Wild Pyromancer and following it with Equality will effectively clear the field of all minions, friend or foe.
Be careful when playing Equality against other classes with cheap board clearing spells, as using Equality puts your creatures at risk. In particular, the mage's Arcane Missiles and Arcane Explosion are an excellent tool for this.
Note that silencing a minion affected by Equality will return its current Health to its original maximum value, even if the minion was previously damaged below this number. This allows Equality to be used in combination with Silences like Wailing Soul to restore the paladin's minions to full Health.
Equality is banned during the Curse of Naxxramas adventure's Heroic The Four Horsemen encounter. If played it will be Countered, accompanied by Kel'Thuzad saying "Equality?! Not on my watch!" No mana will be refunded for the card.