Question:

How will we know how to observe Jewish Law when Moshiach comes, if we will primarily study the Torah’s inner dimensions?

Answer:

When Moshiach comes, we will know instinctively how to conduct ourselves in the ways of the Torah.

When Moshiach comes, the primary branch of Torah study will be the mystical dimensions, which deals with knowledge of G-d’s attributes and qualities.  However, if this is the case, how we know how to observe the mitzvot?

Rabbi Schneur Zalmen of Liadi raises this question, and explains that in the future there will be no lapses of memory.  Once we learn something, it will be imprinted in our memory forever.  Memory loss is a manifestation of impurity and evil spirits, which will evaporate when Moshiach comes.  Furthermore, any memories that we might have lost before Moshiach comes will be restored to us.  Therefore, we won’t need to dedicate as much time to memorizing the details of the Law, and will be able to spend the bulk of our time studying the inner dimensions of Torah.

Additionally, Rabbi Schneur Zalmen explains, in the Messianic era we will be granted an extra level of understanding, and from our study of the Torah’s mystical dimensions, we will be able to infer all the practical laws of Jewish observance.

The Lubavitcher Rebbe adds a unique interpretation:  When Moshiach comes, our evil inclination will be removed, and our nature and instincts will be transformed.  Just as a young child instinctively draws his hand away from fire, we will have a natural aversion to those things forbidden by the Torah, and a natural inclination to do the things the Torah requires.   The details of Jewish Law will be hard-wired into our system, and will not require as much time for us to master.

(Igeret Hakodesh, Rabbi Schneur Zalmen of Liadi, ch. 26; Hilchos Talmud Torah, 10:2; Likutei Sichos, vol. 25, p. 263)