In the days of King David and King Shlomo, the nation was on a high spiritual level. But then, Yaravam ben Nevat caused the nation to sin. So too, in every generation, things change according to the circumstances. Even in the days of the Tannaim (Sages of the Mishnah) and Amoraim, (Sages of the Gemorah) each time period was different from every other. Times were constantly changing throughout history.
This is because all of these events happened in a world conducted by Hashem’s Presence, which is “Memalei Kol Almin.”
In this world, things are arranged like a body: There is a head, arms, legs, and other limbs, each one different from the other, and each limb functioning differently. Also, sometimes one of the limbs is in pain or is weak, etc., or other similar changes that can happen to different body parts.
A body is generally one entity, but, since it is made of different parts working together, a person has many different aspects, and even in each particular body part, there can be many different facets. Similarly, since each time and place is created differently by Hashem, there are always differences between one place and another, and between one era and another. The possibility for so many differences comes from the level of how Hashem is “Memalei Kol Almin” according to the various limitations of the created beings.
So too, in each person specifically: Sometimes, a person falls into thoughts, words, or deeds that are not good, and sometimes he will be struck with sudden thoughts of Teshuvah and good deeds, since “there is a time for everything,” and “one nation (animal soul) will fight against the other nation (Divine soul)” (Bereishis 25:23), meaning that “when one rises up the other one automatically falls,” and “Tzor (capitol city of Eisav) only became established through the destruction of Yerushalayim.” (Rashi on verse ibid.)
Therefore, a person should not become dejected when he sees that sometimes he falls spiritually, since this is the cycle in which Hashem made time, with the ability for things to change. One can also return from his improper conduct and change his path from bad to good.
This entire system of changes applies on the level of worlds that are energized by “Memalei Kol Almin.”
