Jacob Frank claimed to be the reincarnation of the false Messiah Shabbetai Zvi. In the mid-1700’s, he sought to create a new religion that would incorporate both Judaism and Christianity, leading to the formation of the Frankist sect, centered in Poland. Many rabbis of the time, including the Baal Shem Tov, battled the new sect and its leader vigorously and successfully halted their influence.
Link: Belief in Moshiach
We are one because we share a single soul, like a single, brilliant sun shining into many bodies. Since the soul is what counts, that makes us essentially one.
That is the meaning of the mitzvah of the Sukkah—a place that encompasses us all equally, rendering us a single whole.
We are also one because none of us are alike. Each of us reflects a different facet of that same soul, each of us with our strengths and our weaknesses, so that we all need one another to be whole and complete.
That is the meaning of the mitzvah of the Lulav, the Etrog, the Hadassim and the Aravot—four very diverse species, each containing that which the others lack.
And that is why this mitzvah is best done inside the Sukkah: To draw the oneness of our shared soul into the harmony of our diverse bodies.