Rashi explains that Hashem saw that the light was good, but He did not want the light to rule together with or over the darkness. He let the darkness subsist, separating it from the light. This seems enigmatic. Why would Hashem create darkness and light together only to separate them afterwards? Why not simply create two separate entities completely distinct from one another from the beginning? Horav E.M. Bloch z.l., infers an important lesson from this pasuk. From the beginning of creation, Hashem instituted the important principle of separation. Differentiation between two entities does not necessarily occur because they are disparate. On the contrary, separation is in its own right an important and positive act. The division between Am Yisrael and the other nations is not only a result of the negative aspect of developing a relationship with them. Rather, separation and distinction is in itself an important goal for Am Yisrael.
In a similar thesis, Horav Eli Munk z.l., suggests that this havdalah, separation, serves as the prototype for the separation of genders into male and female. Thus, Hashem also distinguished Heaven from earth. In the Havdalah prayer we praise Hashem as “the One Who separates the holy from the profane, light from darkness, Yisrael from the nations, the Shabbos from the six working days.”
Horav Munk explains that in the world scheme the concept of havdalah, separation, serves as a catalyst for man’s existence on earth. Specifically, this universal severance is what gives man his “raison d’etre” in this world. Man is enjoined to transcend these dualisms and infuse the Supreme Unity wherever possible. Everything emanates from one unique source, and eventually returns to it. Man and woman were originally formed as one androgynous being, but were divided afterwards into two separate bodies. The natural tendencies towards the marriage union, whereby together they form one unit is an inherent part of their psyche.
This concept also applies to the various other “separations.” They do not represent a definite state of eternal disjunction. The distinct boundary between light and darkness will be overcome when iuhm kg asj rut rht, , “a new light will shine over Zion”. Similarly, as the source of morality is propagated throughout the world, the breach between Am Yisrael and the nations of the world will close, as everyone unites to serve the one G-d. All semblance of disparity will dissolve and give way to one supreme harmony in belief and worship. Then, the distinction between Shabbos and the six other days of the week will defer to the, hhjk vjubnu ,ca ukufa ouh ohnkug “days which will be completely a Shabbos and rest day for eternal life.”