Sins of the Past

Oracle Text

Until end of turn, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that card would be put into your graveyard this turn, exile it instead. Exile Sins of the Past.

Card Rulings

10/1/2005 The instant or sorcery card is cast from your graveyard, not your hand. You choose modes, pay additional costs, choose targets, etc. for the spell as normal when casting it. Any X in the mana cost will be 0. Alternative costs can’t be paid.
10/1/2005 The instant or sorcery card never gets put back into your graveyard, even if it’s countered. You can’t cast it more than once.