song poetry - Go in Peace - why are we sending the Angels away

On Friday night we welcome the angels by singing Shalom Aleichem the question is why do we tell them:

צֵאתְכֶם לְשָׁלוֹם מַלְאֲכֵי הַשָּׁלוֹם מַלְאָכֵי עֶלְיוֹן

Essentially sending them away that seems to be a quite ungracious host so why do we do it?

Answer

1. Machatzit Hashekel Siman 262: We don't know when they are going to leave. So we ask them to bless us whenever they decide to leave. Similar to "Blessed are you when coming and blessed when leaving".


2. Avnei Nezer: Shalom Aleichem we say to the Malhachei Hashabat that "came" with us from Shul and Tsetchem Leshalom we say to the Malhacei Hachol (Mundane? weekday?) which were with us during the week. Similar to Ya'akov who had 2 groups of Malachim: One for Eretz Yisrael and the second for Chutz Laharetz.