The most limiting feature of all is the limitation of time. The limitation of time means that one object cannot be in two different places simultaneously. Moreover, the concept of time is bound with that of change. This means that when one thing ceases to be and another thing begins to be, a change has occurred. Change can only take place where the unity and infinity of G‑d are hidden, namely, where the continuity of being is not evident.

The most limiting feature of all is the limitation of time

Time is created by way of the process of the extension and retraction of the light and life force as it reaches out to the vessels below and returns to its original place. The "gap" between the reaching out and the returning of the light and life-force, as it pulsates continuously from above, creates time. From moment to moment the light and life force extends "downward", and then retracts, returning to its original place. That which it activated or vitalized "dies", so to speak, as soon as the life force is withdrawn, and then when it reaches down once again, it creates a new being. This change is the origin of time, for time is a measure of change. This process is analogous to a motion picture. Light shining through the constantly changing frames of the strip of film appear to create a continuous scene. In reality, however, each frame in the strip of film is distinct from the previous one; it is only because the movement of the frames is so fast that the human eye is unaware that there are separate images. Thus the scene appears to the eye to be continuous. So too is it with the pulsating of life-force into the physical world — the "gap" between one pulse and the next is so minute, that the scene appears to be continuous.

This reaching out and returning of the life force from above is mirrored in the advance and retreat of the life force below. The pulse which you can feel in your wrist and in your heartbeat is the result of this process. Each time you feel the thump of your pulse or your heartbeat, it indicates that a different "permutation" of the light and life force is enlivening you. Because of this constant renewal, you change from moment to moment. The near perfect state of rectification …needs to be drawn down into this world

In Kabbala, this continuous pulsation or fluctuation is manifested in the world of Asiya, or the world of Action. The essence of the world of Asiya is action. The story of Creation concludes with the words "that G‑d made to do (or to rectify)." The word "to do", in Hebrew la'asot, is derived from the same word as Asiya — action. This world is created for the sake of action, which means rectification. The near perfect state of rectification of the world of Atzilut (see above) needs to be drawn down into this world too. This world is created "incomplete." What it is "lacking" is the revelation of G‑dliness that is found to greater or lesser extent in the supernal worlds. The rectification of Asiya is the revelation of G‑dliness in this world through the actions of man.

The Jewish sages therefore recommend that every person say to himself "for me the world was created." This does not mean one should regard oneself as the center of the universe and everything was created to serve one's ego. Quite the contrary. Rather understand the phrase to mean: "For me the concealment of G‑d was created in order that I should reveal G‑dliness in this world and thereby rectify it." This is the task G‑d created for us: to reveal the inner dimensions, the G‑dliness, contained and yet hidden in this world. Thus, the world of Asiya, the world of Action, is really the ultimate purpose of Creation. For here, more than anywhere else, G‑dliness is hidden. And G‑d can be revealed here even more than in the worlds above, as will be explained.

This ends our basic introduction to the idea of Worlds. Click here to learn about the nature of sefirot in Kabbala.