One of the great insights that Torah teaches about the world is that time itself has a personality. The first six days of the week are not like the seventh. The seventh day, Shabbos, is holy. It is the heart of the week and the soul of creation. When we keep Shabbos we mine it’s spiritual treasures, and bring peace to ourselves, the world and the entirety of humanity. Shabbos is called a miniature of the Garden of Eden.
One of the special ways we enter into the Garden of Eden is by singing. Shalom Aleichem is a special song addressed to the angels of Hashem. First we greet them, then we ask them to bless us, but then mysteriously we ask them to go away. This structure mirrors many deep things. When Ya’akov Avinu, our forefather Jacob, entered into the land of Israel after a long exile, he saw the angels that were guarding the land outside of Israel ascending back to heaven. He also saw the angels guarding Israel coming down from heaven.
So it is in our own lives. We are saying goodbye to the angels guarding us during the first six days of the week, which are now going up to heaven, and we are welcoming the angels coming down, which are protecting us over Shabbos. Thus, as we cross the border from the mundane into the holy, from the six days of the week into the seventh, we sing and rejoice over the transition that is happening around us.
Let’s turn our attention to another reason why we ask the angels to leave. When we were exiled from the Garden of Eden, Hashem placed an angel to block the entrance, thereby stopping us from reentering the Garden. Those fiery angels remain there until we fix everything we need to, both in ourselves and the world. Since Shabbos is a miniature of the Garden of Eden, when we ask the angels to leave, we are asking them to let us back into Paradise for Shabbos. Interestingly, our holy tradition teaches that even though Adam and Eve were exiled from the Garden before Shabbos, nonetheless Hashem let them back in for Shabbos!
On a deeper level, we know that when Mashiach comes there won’t be any barriers separating us from Paradise. So, every Friday night we ask not just for the angels to go away temporarily, but that they stop blocking the entrance to the Garden of Eden forever. That will usher in the next era of humanity. A period we call Yom Sheculo Shabbos, the day that will be all Shabbos.