Angels, Places and Times
The Patriarch Yaakov, we learn in the Torah portion which Jews will read this Shabbat throughout Eretz Yisrael and the world, had a most dramatic experience as he was on the verge of leaving the Holy Land in order to find his mate in the foreign land to which his parents had directed him. He spent a night on the mountain where the Beit Hamikdash would someday stand and, explains the Midrash, he was exposed to a prophetic vision of its construction and destruction.
How does this implied vision of the future connect with the vision which the Torah so explicitly describes of a ladder reaching to Heaven with angels climbing up and down on it?
The angels descending, say our Talmudic Sages, were the ones who escorted Yaakov in Eretz Yisrael and now returned to their Heavenly base once their mission was completed, and they were to be relieved by other angels descending to escort him outside of the Holy Land. Every angel has its own special mission and is not charged with more than one. The protection that Yaakov required while in Eretz Yisrael was not the same as what he required outside the land. Since the experiences of the Patriarchs are an indication of what their descendants would endure, it is safe to say that the dangers which Jews face, physical and spiritual, are not the same in Eretz Yisrael as they are elsewhere, and Heaven provides us with the protecting angels we need in each place.
Just as there is a difference between one place and the other there is a difference between one time and another. The challenges Jews face when they have no Beit Hamikdash are not the same as those they faced when they had one. Yaakov was therefore shown the challenges which his progeny would face in each era, comforted by the Heavenly guarantee of protection through His guardian angels which would be with Israel forever.