The Yom Tov of Shmini Atzeres makes an appearance at the very end of our sedra. Chazal tell us that HaShem instituted Shmini Atzeres because He declared ‘your separation is hard for me.’
In other words, HaShem wanted us to stay and celebrate ’with Him’ one day longer. But how exactly does one day make a difference here; after this day we will still have to separate from HaShem, so to speak?
One idea is that ‘your separation’ here refers to our rushing away from Sukkos. HaShem wants to make sure that we ingest and digest all the themes and messages of Sukkos, as opposed to rushing back to our ‘normal’ everyday lives.
Thus, He gave us an extra day called Shmini Atzeres to internalise and develop everything that we gained from Sukkos.
Alternatively, ‘your separation’ refers to the unity amongst Klal Yisrael. For for the entire duration of Sukkos we have been offering 70 cow offerings corresponding to the 70 nations of the world (amongst other offerings); we were offering korbanos on their behalf too. And when we are ‘on show’ for the other nations of the world it is very easy to preserve unity and act in a unified way. But HaShem feared that after the Sukkos korbanos were over then we’d sink to national disunity, and so said ‘your separation (from each other) is difficult for me’ and instituted Shmini Atzeres for us to celebrate together purely as the Jewish People and forge unity with each other.
