As Gideon's Intervention enters the battlefield, choose a card name.
Your opponents can't cast spells with the chosen name.
Prevent all damage that would be dealt to you and permanents you control by sources with the chosen name.
4/18/2017 You may choose the name of a land card. Cards with that name can still be played (since lands are never cast), but damage they would deal to you and your permanents will be prevented.
4/18/2017 If you choose the name of a split card, you choose one name, not both. For example, you could name Failure or Comply, but not Failure // Comply. Opponents are still allowed to cast the half you didn’t choose.
4/18/2017 You must choose the name of a card, not the name of a token. For example, you can’t choose “Zombie” or “Ragavan.” However, if a token happens to have the same name as a card (such as an embalmed creature token), you can choose it.
1/19/2018 There are many important moments in the story, but the most crucial—called “story spotlights”—are shown on cards. These cards have the Planeswalker symbol in their text box; this symbol has no effect on gameplay. You can read more about these events in the official Magic fiction at http://www.mtgstory.com.