[to behold] with immortal spirit the immortal Aion and lord of the fiery diadems, hallowed with holy hallowings, holy, while my human soul-power withdraws for a little,

The vision's object is Aion — not 'an age' here but the god Aion, Time itself made a person, 'immortal' and crowned with 'fiery diadems' (the circling fires of the heavens read as a king's many crowns). The magical and gnostic worlds worshipped Aion as a supreme figure; to behold him is to see the whole of time at once, from inside. Two things happen to the initiate in the same breath. He is hallowed — the line piles the root up threefold, hagíois hagiastheìs hagiásmasi hágios, 'with holy hallowings hallowed, holy,' the sound itself consecrating by repetition. And his ordinary self steps aside: his human soul-power withdraws for a little (hypexestṓsēs, quietly retires). This is the rite's psychology stated plainly — the mortal faculty must vacate, briefly, so that something immortal can look through the space it leaves. The psychikḗ dýnamis, the natural soul, is exactly what later writers set below the spiritual; here it is politely asked to leave the room.