Shalom Aleichem: Time & Space
Rashi comments that the Angels rising and descending the ladder in Jacob’s dream, were the Angels who accompanied Jacob in Israel climbing up the ladder, and the Angels, that would protect him when he was outside of Israel, descending.
Each place has its own specific angels, and so too, does each time. There are weekday Angels and Shabbat Angels. One verse says, “For his Angels He will command to accompany you,” and another verse say, “God encamps Angels surrounding those who are in awe of Him.” The Zohar explains that the Angels that accompany are weekday Angels, that move with us, however on Shabbat, “No man shall leave his place,” so these are the Angels that ‘camp” around us. (Vayichaltzeim as in Ritzei V’hachlitzeinu)
Just as there are Mitzvot specific to Israel, and Mitzvot for specific times, so too, all souls are like Angels, with a specific mission to accomplish in this world. The mission is specific to time and place.
We welcome the Shabbat angels with Shalom Aleichem, and we bid farewell to the weekday Angels with Tzeitchem L’Shalom. (My family has the custom to wave goodbye to the angels that are leaving.) (Sefat Emet, Vayeitzei 5661 7 Tehillim 34:8)