Studying and Teaching

Shalom Rabbi, I understand Torah is written on at least 3 levels. Can you please tell me what they are and what they are called. I understand the first level is the practical and the third is the spiritual but I do not know what the second is.

OS 099I recently read the following statement of the Vilna Gaon: "The ultimate redemption of the Jewish People (Geula) will come about only through learning Torah; And primarily through learning Kabbalah [Torah's deep secrets]. Since I don't learn Kabbalah, is my Torah study insignificant with respect to bringing about the final redemption?

Why does it seem to be the norm to study Torah with a study partner instead of just sitting alone with a book?

are you allowed to read or study Chumash at night? if not, what is the reason? what is the cutoff time based on? what about on Shabbat or Yom Tov?