Auriok Steelshaper is a rare Creature — Human Soldier card from Mirrodin (MRD), collector number 4. Current market price: $0.85 (foil $16.45), TCGplayer market prices via Scryfall.
Equip costs you pay cost {1} less. As long as this creature is equipped, each creature you control that's a Soldier or a Knight gets +1/+1.