Gideon's Phalanx

• WWizards of the Coast2015-06-22
  Official Ruling
  Check to see if there are two or more instant and/or sorcery cards in your graveyard as the spell resolves to determine whether the spell mastery ability applies. The spell itself won’t count because it’s still on the stack as you make this check.
• WWizards of the Coast2015-06-22
  Official Ruling
  If the spell mastery ability applies, the four Knight tokens will also gain indestructible until end of turn.

Rulings via Scryfall