Where Angels Fear to Tread
[Yaakov] dreamed and behold there was a ladder standing on the earth with its top reaching heaven, and behold, angels of God were going up and down on it.
(Bereishit 28:12)
Heaven is the abode of angels, so it would seem more logical for the angels in Yaakov’s prophetic dream to first descend and then ascend. This led our Sages to conclude that there were two sets of angels – those who had hitherto escorted Yaakov while he was in Eretz Yisrael, and those who were to become his escorts when he left the Land on his way to the home of his uncle, Lavan.
The Eretz Yisrael angels don’t leave the Holy Land, so they went up the ladder back to Heaven, while the angels in charge of escorting outside of Eretz Yisrael came down to take over this responsibility.
The need for different angels may be understood in the light of our Sages’ state- ment (quoted by Rashi in Bereishit 18:2), that an angel is never charged with two different missions. Angelic protection in Eretz Yisrael is so distinct from that provided outside the Land that it might have constituted assigning two different missions to the same angel.
(Bereishit Rabbah 68:12)