[The Symbolism of Freemasonry, by Albert G. Mackey, 1882 - Excerpt - Linked Above]
In an investigation of the symbolism of the Winding Stairs we shall be directed to the true explanation by a reference to their origin, their number, the objects which they recall, and their termination, but above all by a consideration of the great design which an ascent upon them was intended to accomplish.
The steps of this Winding Staircase commenced, we are informed, at the porch of the temple; that is to say, at its very entrance. But nothing is more undoubted in the science of masonic symbolism than that the temple was the representative of the world purified by the Shekinah, or the Divine Presence. The world of the profane is without the temple; the world of the initiated is within its sacred walls. Hence to enter the temple, to pass within the porch, to be made a Mason, and to be born into the world of masonic light, are all synonymous and convertible terms. Here, then, the symbolism of the Winding Stairs begins.