“Enq: But Christianity teaches the same. It also preaches progression.
Theo: Yes, only with the addition of something else. It tells us of the impossibility of attaining Salvation without the aid of a miraculous Savior, and therefore dooms to perdition all those who will not accept the dogma. This is just the difference between Christian Theology and Theosophy.
The former enforces belief in the Descent of the Spiritual Ego into the Lower Self; the latter inculcates the necessity of endeavoring to elevate oneself to the Christos, or Buddhi state.
Enq: By teaching the annihilation of consciousness in case of failure, however, don’t you think that it amounts to the annihilation of Self, in the opinion of the non-metaphysical?
Theo: From the standpoint of those who believe in the resurrection of the body literally, and insist that every bone, every artery and atom of flesh will be raised bodily on the Judgement Day – of course it does.
If you still insist that it is the perishable form and finite qualities that make up immortal man, then we shall hardly understand each other.
And if you do not understand that, by limiting the existence of every Ego to one life on earth, you make of Deity an ever-drunken Indra of the Puranic dead letter, a cruel Moloch, a god who makes an inextricable mess on Earth, and yet claims thanks for it, then the sooner we drop the conversation the better.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 