Oath of Jace is a rare Legendary Enchantment card from Oath of the Gatewatch (OGW), collector number 60. Current market price: $0.30 (foil $0.75), TCGplayer market prices via Scryfall.
When Oath of Jace enters, draw three cards, then discard two cards. At the beginning of your upkeep, scry X, where X is the number of planeswalkers you control.