The essence of the Manifestations of God is the same before and after their Declarations

…the Manifestations of God have ever been and will ever be luminous Realities, and no change or alteration ever takes place in Their essence. At most, before Their revelation They are still and silent, like one who is asleep, and after Their revelation They are eloquent and effulgent, like one who is awake. 

- ‘Abdu’l-Baha  (Table talks in Akka, authenticated by ‘Abdu’l-Baha; ‘Some Answered Questions’ – 2014 revised translation by the Baha’i World Centre)