"…Anyone whose fear of sin comes before his wisdom, his wisdom will endure…" (Avot 3:9)

Fear as a key to the Outer Gates

The fear of sin which must come before wisdom is the lower level of fear. A person fears to rebel against the Holy One, blessed is He, and cause a blemish in his thought, speech, or power of action. Such fear is the key to the outer gates of Torah, and in this way his wisdom will endure. This is what Rabbah bar Rav Huna said: Any man who has Torah learning but not awe of Heaven is comparable to a treasurer who was given the keys to the inner sanctum but not the keys to the outer courtyard. Hence, how can he enter at all? [Tzemach Tzedek, Or HaTorah Pinchas, vol.1 p.219]

Fear of sin and Torah

Our Mishna refers to a person who embodies two special qualities:
1) He is wise - he himself learns Torah, and he teaches it to others;
2) He fears sin - he loves mitzvot and hates sin. Only when his fear of sin comes before his wisdom will he live the Torah and wed himself to it…

Regarding both of these, the Mishna informs us that not only must the fear of sin come before the acquisition of wisdom, but that fear of sin is directly connected with fulfilling and reinforcing the Torah.

The reason for this is that the Torah relates to the faculties of intellect, whereas fear of sin is an emotional quality. There is a fundamental difference between the nature of emotions and the nature of intellect. A person does not always live an intellectual concept, meaning that the concept is not always absorbed into his essence. A person of broad understanding can generally live with ideas which are abhorrent to him. In contrast, when a person embraces a certain emotional quality, he hates with a passion whatever opposes it.

When a person who learns Torah does not place the fear of sin before the acquisition of wisdom and knowledge, there is no guarantee that he and the Torah will become fully wed. On the contrary, at times the Torah could turn into an elixir of death for him. Only when his fear of sin comes before his wisdom will he live the Torah and wed himself to it, so that it becomes an elixir of life, and in this way it will endure.[Rabbi Yosef-Yitzchak Shneersohn, Sefer HaMa'amarim Yiddish p.167]

Connecting the soul with its root

The Mishna does not refer to a person just beginning to learn Torah, but rather to one who is already a "chacham", a truly wise person. According to the definition of a "chacham" in Chassidut, he is a scholar well-versed in the Divine Wisdom. Regarding such a sage the Mishna states that his fear of sin must come before his wisdom, if his wisdom is to endure. However, if this is not so, his wisdom will not endure. The soul is only partially revealed in the body…

When a person begins learning he is told that he should occupy himself with Torah, despite the fact that this might not be for the proper reasons, for eventually he will come to learn for the proper reasons. However, once he has already reached the level of learning with the proper intentions, his fear of sin must come before his wisdom. This does not mean that one precedes the other chronologically, but rather that his fear of sin precedes his eagerness to acquire wisdom in terms of priority. If one were to balance the two on a scale, his fear of sin would "outweigh" his eagerness for knowledge.

As is known, the soul is only partially revealed in the body. In fact, only its radiance and aura pervade the body, while the essence of the soul remains "above" him, in what is known as the aspect of "makif ", that which transcends the individual and cannot be contained within him. Placing fear of sin before wisdom alludes to an elevated type of divine service in which a person draws down the root and source of his soul, and connects it to the lower aspects of the soul which pervade the body of man.

The root and source of the soul is even more elevated than the wisdom of Torah. Hence, when a person binds the root and source of his soul to the soul within the body, and he draws the root of his soul (by placing fear of sin first) down to the level of the wisdom he has acquired through Torah - then his wisdom will endure. [from Sichas Tavo 5728 by the Lubavitcher Rebbe]