Honorable Passage is a special Instant card from Time Spiral Timeshifted (TSB), collector number 9. Current market price: $0.27 (foil $2.33), TCGplayer market prices via Scryfall.
The next time a source of your choice would deal damage to any target this turn, prevent that damage. If damage from a red source is prevented this way, Honorable Passage deals that much damage to the source's controller.