The Zohar, Chapter “Chayei Sarah (The Life of Sarah),” Item 203: When a person is destined to account for his deeds, before he leaves the world, this day is a day of reckoning, when the body and the soul report. Afterwards, the soul departs the body and parts with it, and the body, which was created from dust, returns to dust and everything returns to the place from which it was taken. And until the time when the Creator revives the dead, everything will be concealed from it.
Equally in our spiritual advancement, we don’t know what the upper rung means, or what it is that constitutes our next state. Today as well, none of us know what the next minute will bring to our lives. We can try to predict, but it won’t help. Nobody can grasp the future. The next rung is always concealed and it is revealed either through the path of suffering (Beito, in time), or through the path of goodness (Ahishena, accelerated time).