Duty Beyond Death is a uncommon Instant card from Secrets of Strixhaven Mystical Archive (SOA), collector number 69. Current market price: $0.34, TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, sacrifice a creature. Creatures you control gain indestructible until end of turn. Put a +1/+1 counter on each creature you control. (Damage and effects that say "destroy" don't destroy those creatures.)