Indeed there is a practical need, especially for the posek, to be intimately knwoledgable and constantly involved in halakhic reasoning, but why is gemara the essential spiritual path for the Jew?
In this post we will explore the idea that learning nigleh must proceed learning nistar.
The Rambam (Hilkhot Yesodei ha’Torah, 4:13) writes: These four chapters, with these five mitzvoth [to know that there is a G-d, to not entertain the possibility of the other gods, to designate Him as One, to fear Him, and to love Him], are what the early Sages called “Pardes,” [the garden], as it says “four entered into Pardes.” Even though that [these four] were great men of Israel and great Sages, they were not all able to know and grasp these things properly. I am of the opinion that it is only one who has filled his belly with bread and meat is fit to stroll in the garden; “bread and meat” is the knowledge of the forbidden and permitted, and similar things in all other mitzvot. [This is the case] even though that these things were called by the Sages “a small thing,” as they said, “ma’aseh b’reishit and ma’aseh merkavah are a great thing and the argument of Abaye and Ravva are a small thing.” Nevertheless, it is fitting that these [a small thing] precede these [a great thing],for they settle the mind of man first, and, furthermore, they are a great goodness that the Holy One, blessed is He, gave in order to settle this world (?) in order to inherit the life of the world to come - it is possible for all to know these things; a child or adult, a man or woman, a broad thinker or a limited thinker."
The Rambam first discusses why learning gemara should precede learning philosophy (which is the real goal of Judaism according to the Rambam). It settles the mind. It makes a person grounded in this world before they let their head spin as they contemplate abstract reality. So many spiritualities lead a person to become imbalanced - "al tehi tzadik harbeh!" First live in this world, within the structure of halakha, and then work on understanding the imperceivable.
"Settling the mind" might also mean that this "small thing" trains a person to think abstractly in a clear way. This seems to be what R. Kook writes in Orot ha'Torah 6:9. This would then imply that the three Sages who did not successfully “stroll in the garden” did not train their mind enough, while R. Akiva did. This would be problematic since a) it does not give much hope to people learning gemara (especially today!) that they will successfully train their mind to the extent that they can learn philosophy; b) it does not explain why learning logic (which the Rambam himself wrote a book on) would not be sufficient and replace the need for gemara.
The Rambam’s second point is that learning halakha and gemara (although to a lesser extent) is democratic. Hashem did a tremendous kindness in giving the Torah which allows for all of Israel to inherit a portion in the world to come [this would seem to be a contradiction to Moreh Nevuchim which views philosophy as the way to the world to come, but see Iggrot ha’Rambam, Ma'amar Kiddush Hashem which says that even a simple person who dies al kiddush Hashem merits the world-to-come]. In other words, learning what Hashem wants of us, in all its minute detail, is inherently important, and need not lead to learning philosophy. The greatness of Torah is that it is "down-to-earth" and "not in the heavens." The crown of Torah is available for all.
There is another way to understand the temporal priority of nigleh before nistar. The halakha is also conceptual and can be further and further abstracted into philosophical or spiritual concepts. R. Soloveitchik's line at the end of Halakhic Mind is often quoted: "Out of the sources of Halakha, a new world view awaits formulation." His student R. Wurzburger continued this tradition, calling it "meta-halakhic propositions, which contain the ontological and axiological presumptions which form an integral part of the halakhic system." For example, the halakha can teach us abut the sanctity of human life or of the land of Israel, the nature of time and a heirarchy of values. Also see Jed Lewinsohn's "Philosophy in Halakha: The Case of Intentional Action" in The Torah u-Madda Journal (14/2006-07).
We will return to this idea when discussing the kabbalistic view of the Torah.