(2) The souls of the Jewish people are the letters of the Torah. This is a basic teaching from the Zohar. It has number of really interesting implications I hope to get into one day, for now just a simple insight.
(3) There is a very basic halachah. When there is a doubt regarding the validity (kashruth) of one of the letters in a Torah scroll, we ask a child, not an overly intelligent child, nor an overly simple child, but an average child who doesn't yet know how to read but has already learned the alphabet. We ask that child what letter the letter in question looks like, if the child answers correctly, then the letter is kosher, and Torah scroll can continue to be used to learn and read from. If the child says it looks like a letter other than the intended letter, then the Torah scroll is not kosher to be used until it has been corrected.
Taken together, these three pieces of information seem to imply something very deep and very special about Hassidut. The Baal Shem Tov and all those who followed him aspired to be the simple child who could correctly recognize the hebrew letter (soul) hidden within each one of us. If the Rebbes were simple and 'childish' (in the relevant sense mentioned above) then they could bring any Jew over to the side of 'Kashrut' simply by recognizing the Jewish soul hidden within him or her.