This week's Torah portion, Vayishlach, opens

This week's Torah portion, Vayishlach, opens with the words "Jacob sent malachim before him to Esau his brother."Although the word "malachim" is usually translated in this verse as "messengers," Rashi, the foremost Torah commentator, tells us that Jacob sent "malachim" in the literal sense: "angels" - actual celestial beings.
Why did Jacob find it necessary to send the angels? Furthermore, in light of the principle that "one angel cannot perform two missions at the same time," by dispatching angels to Esau, Jacob was seemingly diverting them from their Divinely-appointed missions in the heavens.
Chasidic philosophy provides us with the answer by explaining the inner meaning of the angels' mission.
Jacob understood that the entire purpose of creation is the separation of good from evil and the restoration of the "sparks of holiness" to their G-dly source; indeed, this was his sole intention when he set out for the spiritually impure Charan.
Jacob also understood that his service alone was insufficient to achieve his goal; the participation of his brother Esau was also necessary.
Esau, described as "a man of the field," is symbolic of the highest G-dly light fallen to the lowest depths; thus, the ultimate Redemption with Moshiach will only come about when gentiles as well as Jews have reached a state of perfection.
After 20 years of service in Charan, Jacob was ready for the Redemption; he hoped that in the interim Esau had sufficiently refined himself and was ready as well. This is alluded to in Jacob's reference to "a donkey" upon greeting his brother - symbolic, as our Sages tell us, of King Moshiach, who is described as "riding on a donkey."
For such an important mission - indeed, the most important mission of all, the fulfillment of the ultimate goal of creation -- only the finest emissaries would do: celestial angels. For them, this was not an inconvenience at all; on the contrary, it was a very great merit, as they too joyously anticipated the Redemption.
Unfortunately, Esau had not yet completed his service. "We came to your brother," the angels told Jacob on their return, "to Esau." In other words, Esau is still the same person as he was 20 years ago, he hasn't changed. Hearing this, Jacob realized that the road to Redemption would be long and hard, as he told his brother, "I will go ahead slowly."
This, however, was long ago; today, after thousands of years of service, most particularly after the revelation of Chasidut, the preparation for Moshiach, the entire world is ready for the Redemption. All that is left is for it to become manifest in the physical world; may this occur at once.

Adapted from Sefer HaSichot of the Rebbe, 5752, Vol. I