Intervention Pact is a rare Instant card from Future Sight (FUT), collector number 8. Current market price: $4.27 (foil $22.66), TCGplayer market prices via Scryfall.
The next time a source of your choice would deal damage to you this turn, prevent that damage. You gain life equal to the damage prevented this way. At the beginning of your next upkeep, pay {1}{W}{W}. If you don't, you lose the game.