Rush of Battle is a common Sorcery card from Khans of Tarkir (KTK), collector number 19. Current market price: $0.05 (foil $0.36), TCGplayer market prices via Scryfall.
Creatures you control get +2/+1 until end of turn. Warrior creatures you control gain lifelink until end of turn. (Damage dealt by those Warriors also causes their controller to gain that much life.)