Wall of Stone [International Collectors' Edition] Born of the Gods They only specify the consequences

They only specify the consequences should you fail

Set: Unlimited Edition Type: Enchantment Rarity: Rare Cost: {R}{R} At the beginning of each player's upkeep

Set: Unlimited Edition Type: Artifact Rarity: Uncommon Cost: {4} {3}

Set: Commander 2011 Oversized Type: Legendary Creature — Human Wizard Rarity: Mythic Cost: {2}{G}{U}{R} Whenever you cast an instant or sorcery spell

They likely refer not to one mage

Wall of Stone [International Collectors' Edition] Born of the Gods They only specify the consequencesSet: International Collectors' Edition Type: Creature Wall Rarity: Uncommon Cost: {1}{R}{R} Defender (This creature can't attack.) The Earth herself lends her strength to these walls of living stone, which possess the stability of ancient mountains. These mighty bulwarks thwart ground based troops, providing welcome relief for weary warriors who defend the land.