You may cast up to one target instant card and/or up to one target sorcery card from your graveyard each with mana value X or less without paying their mana costs. If a spell cast this way would be put into your graveyard, exile it instead. If X is 10 or more, copy each of those spells twice. You may choose new targets for the copies.
The copies that Finale of Promise creates are created on the stack, so they're not "cast." Abilities that trigger when a player casts a spell won't trigger.
03-05-2019
wotc
If the spell that's copied is modal (that is, it says "Choose one—" or the like), the copies will have the same mode or modes. You can't choose different ones.
03-05-2019
wotc
As Finale of Promise resolves, first you cast the target instant card and/or the target sorcery card in either order. Then, if X is 10 or more, you copy each of those twice and put the copies on the stack in any order. The copies will resolve before the original spells.
03-05-2019
wotc
You can't choose to pay any additional costs for the copies. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.
03-05-2019
wotc
A split card that's an instant and a sorcery card may be the target of Finale of Promise twice. However, once you cast that card once, it can't be cast a second time.
03-05-2019
wotc
If you cast a card "without paying its mana cost," you can't choose to cast it for any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs, such as that of Spark Harvest, you must pay those to cast the card.
03-05-2019
wotc
If a spell has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
03-05-2019
wotc
If the spell has damage divided as it was cast, the division can't be changed (although the targets receiving that damage still can). The same is true of spells that distribute counters.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.