Whispersteel Dagger — ruling 1

You don’t choose a card to cast as Whispersteel Dagger’s ability resolves. You simply get a permission to cast one later.

Whispersteel Dagger — ruling 2

You must follow the normal timing permissions and restrictions for the spell you wish to cast.

Whispersteel Dagger — ruling 3

You’ll still pay all costs for a spell cast this way, including additional costs. You may also pay alternative costs if any are available.

Whispersteel Dagger — ruling 4

In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If you leave the game, any spells and/or permanents you control from Whispersteel Dagger’s ability are exiled.

Whispersteel Dagger : règles, fonctionnement et interactions (MTG)

Whispersteel Dagger is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Equipped creature gets +2/+0. Whenever equipped creature deals combat damage to a player, you may cast a creature spell from that player's graveyard this turn, and you may spend mana as though it were mana of any color to cast that spell. Equip

How it works : Whispersteel Dagger

Original English text — Wizards of the Coast / Scryfall

#1September 25, 2020· Wizards of the Coast
You don’t choose a card to cast as Whispersteel Dagger’s ability resolves. You simply get a permission to cast one later.
No other card is named in this ruling.
#2September 25, 2020· Wizards of the Coast
You must follow the normal timing permissions and restrictions for the spell you wish to cast.
No other card is named in this ruling.
#3September 25, 2020· Wizards of the Coast
You’ll still pay all costs for a spell cast this way, including additional costs. You may also pay alternative costs if any are available.
No other card is named in this ruling.
#4September 25, 2020· Wizards of the Coast
In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If you leave the game, any spells and/or permanents you control from Whispersteel Dagger’s ability are exiled.
No other card is named in this ruling.