After the soul departs from the body, it undergoes a process of rectification.
The first stage of this process is known in the kabbalistic literature as the “hollow of a sling.”
Simply put, this is the most comprehensive overview possible of our lives in this world.
It is similar to the old saying that “when you die, your whole life passes before your eyes.”
While we are alive, our active memories usually don’t include our entire life’s course.
There is a natural process of forgetting, meaning that even memories existing in the brain are not available to consciousness.
Additionally, while we are alive, the memories in our consciousness tend to focus exclusively on certain flash-points, whether of happiness or sorrow.
In the “hollow of a sling,” by contrast, the soul – which is no longer connected to the body – apprehends the whole of its former life process at once.
Indeed, this stage is commonly considered a stage of punishment, but its actual purpose is to bring the soul to a state of complete awareness.
The soul acquires a certain comprehension of the details of events that were forgotten or hidden during its time in this world.
Because the various components of that lifetime are no longer relevant, the soul absorbs a more comprehensive sense of the entirety of its life while in the body.
–Rabbi Adin Steinsaltz