Soul of Theros

Oracle Text

Vigilance

4WW: Creatures you control get +2/+2 and gain first strike and lifelink until end of turn.

4WW, Exile Soul of Theros from your graveyard: Creatures you control get +2/+2 and gain first strike and lifelink until end of turn.

Card Rulings

7/18/2014 You can activate the last ability only if the Soul is in your graveyard.
7/18/2014 Exiling the Soul from your graveyard is part of the last ability’s activation cost. A player can’t remove the Soul in response to prevent you from activating the ability.