Hazoret's Undying Fury is a rare Sorcery card from Hour of Devastation (HOU), collector number 96. Current market price: $0.25 (foil $0.39), TCGplayer market prices via Scryfall.
Shuffle your library, then exile the top four cards. You may cast any number of spells with mana value 5 or less from among them without paying their mana costs. Lands you control don't untap during your next untap step.