Color= Black  Type= Instant  Cost= BB A(R)/B(R)/U(R)  
Text (ABU+errata): Look at target opponent's hand and choose a card from it. That player plays that card with his or her own mana, but you make all decisions it calls for. The player is required only to use mana from his or her mana pool and mana that can be drawn from lands. [Oracle 1999/09/03]

The caster of Word of Command controls all aspects of the spell they have the opponent cast, including the amount of mana and target of the spell. Note that if the spell just enables something, you cannot power it in addition to casting it. For example, you cannot cast Pestilence then tap additional mana to power the card, or summon a Nether Shadow and declare an attack with it. Spells with an X mana cost have X decided by the caster of Word of Command. [WotC Rules Team 1994/01/24] The decisions apply to ones made on announcement and ones made on resolution. [D'Angelo 1995/04/11]
Since this spell is an instant, your opponent gets a chance to respond to it as normal. Once this spell resolves, you look at your opponent's hand and choose a spell or land. [D'Angelo 1999/10/29] Note that it is common practice to respond to Word of Command by using up any spells or mana you have prior to letting it resolve.
During the resolution of this spell, that player plays the chosen card. [D'Angelo 2003/11/14]
Your opponent cannot counter the Word of Command after letting you look at his or her hand, but they can attempt to counter the spell you force them to play. [WotC Rules Team 1994/01/24]
You must order your opponent to play a spell or play a land if it is possible to do so. [D'Angelo 1994/10/01]
The spell which is played is considered as being played by the player targeted by Word of Command and not by the caster of Word of Command. [Arab FAQ 1994/01/05]
You can make them play anything that they could legally play if the spell stack was empty. So a sorcery spell can be played if it is their main phase, and so on. Since they do get to play the spell as if the spell stack were empty, it is possible to make them play a sorcery when the spell stack is not actually empty. [Gray 1999/10/27]
The spell being cast by Word of Command's effect can be responded to as normal once it is on the stack. [D'Angelo 1999/10/29]
You do get to choose which lands get tapped. [bethmo 1994/06/01] This means you can choose ones with Psychic Venom or other bad effects on them, but does not allow you to tap a wrong amount (or color) of mana (possibly causing mana burn) if there is a possible way to tap the right amount of mana. For example, if one Forest and one Forest with Wild Growth are available, you may not use the one with Wild Growth to cast Giant Growth (cost 'G'). [Aahz 1994/08/01] You can make them choose an optional mana generating ability of the land that is tapped, such as making them sacrifice a Dwarven Ruins. [WotC Rules Team 1994/12/15]
You may Command your opponent to play a land (if they have not already done so this turn). [Aahz 1994/06/01]
If used with a Demonic Tutor being the card the other player casts, you do not get to look through that player's library. You get to name a card for them to take. If it is in the library, they take it. If not, you name another card. Repeat until you name one that they have. [D'Angelo 1995/04/11] Remember that even on-resolution decisions are made by the Word of Command caster.
If there is a non-mana way to cast a spell, as with Pitch Spells, you may require that way to be used if it is possible to do so. [D'Angelo 1997/03/26]
To "play a card" is to either announce a spell or to put a land into play using the main phase special action. [D'Angelo 1999/01/18]
Extended tournaments (see Rule 803) have always banned this card.