The foundational scriptural teaching is stated three times in Tanach: Mishlei 1:7 declares that fear of God is the beginning of knowledge, Mishlei 9:10 that fear of God is the beginning of wisdom and knowledge of the Holy One is understanding, and Tehillim 111:10 that the beginning of wisdom is reverence toward God and all who practice it gain sound understanding.
The Gra (Beur HaGra on Mishlei 1) unpacks this foundation directly: the entire purpose of Mishlei is to attain wisdom, discipline, and understanding, but fear of Hashem is the indispensable root without which wisdom and discipline cannot take root or endure, since only one who fears Hashem will study to know which paths to guard himself from, whereas one lacking this fear finds his wisdom overturned and useless — a reading that gives halachic weight to the relational dependence between yirah and chochmah.
The Gra extends this analysis in his commentary on later chapters: the Gra (Beur HaGra on Mishlei 9) resolves the apparent circularity of the teaching 'if there is no fear there is no wisdom and if there is no wisdom there is no fear' by distinguishing the order of thought from the order of action — in thought, fear is the goal and therefore comes first, while in practice wisdom comes first and generates fear — and the Gra (Beur HaGra on Mishlei 15) adds that fear of punishment leads to wisdom, and wisdom in turn elevates a person to fear of God's greatness.
Even Sheleimah 8:8, drawing on the mishnah in Avot 3:9, explains that when fear of sin precedes wisdom, the wisdom endures, because the one who fears searches his learning with great effort to know the path he must walk, and what a person finds through great exertion becomes beloved to him and preserved in memory — whereas one without fear of sin, even studying many times, will not truly find, since the matter does not sit upon him.
Even Sheleimah 5:5 distills the progression into its barest form: fear of punishment leads to wisdom, and wisdom leads to fear of God's exaltedness — a two-stage ladder from initial constraint to elevated awe.
The Rishonim ground the same principle in the act of contemplation itself: Mishneh Torah, Foundations of the Torah 2:2 teaches that when a person contemplates God's great and wondrous works and perceives in them a wisdom without measure or end, he immediately loves, praises, and glorifies, and yearns with great desire to know the great Name — and that very same contemplation causes him to recoil and fear, recognizing himself as a small and lowly creature standing before perfect knowledge, while Chovot HaLevavot, Sha'ar HaBechinah 1 identifies the essence of bechinah as contemplating the signs of the Creator's wisdom in creation and weighing them within the soul to the capacity of the examiner's understanding.
Mishlei 2:1–6 frames the same dynamic as a demand on the seeker: only one who makes his ear attentive to wisdom, calls out to understanding, and searches for it as for buried treasure will then understand the fear of God and attain knowledge of God — a conditional that Mesillat Yesharim, Introduction seizes upon to argue that fear of God is not a byproduct of philosophy or medicine or legal study but specifically the fruit of this deliberate, treasure-hunting search.
The Alter of Kelm's Chochma uMusar presses this structure into a practical discipline: Chochma uMusar 1 p. 125 and Chochma uMusar 1, Maamar 60 teach that human nature inclines a person to attribute events to chance rather than divine providence, and that extensive contemplation of God's miracles — both the hidden ones of daily life and the famous ones known throughout the world — is the primary remedy to uproot this nature and properly accept the yoke of heaven; Chochma uMusar 1 p. 50 adds that a person has an explicit Torah obligation to direct his thought and intellect toward wisdom, which is impossible without clear knowledge, and that this rational knowledge naturally brings about sensory feeling as well.
The Alter teaches further that this practice must be structured and regular: Chochma uMusar 1 p. 250 holds that through fixed times of contemplating faith, intellect, and knowledge, one's fear of Hashem will gradually cease being a merely learned commandment and progress toward serving Hashem for its own sake, whereas one who does not arrange his thoughts for constant contemplation will remain trapped in futile thoughts — a point he anchors in Chochma uMusar 1 p. 249, which cites Rabbeinu Yonah's ruling that those who do not arrange their thoughts to contemplate continually in fear of Hashem have only a fear learned as a human commandment rather than authentic service.
Chochma uMusar 1 p. 362 brings the structure to its culmination: a person must exert effort to establish fear of Hashem through intellectual understanding and knowledge, and if the roots of faith become firmly grounded in that foundational understanding, then even when he encounters particular matters he might otherwise rationalize away, the general fear of Hashem he possesses through intellect and knowledge will continually rouse him to strengthen his fear and thereby fulfill the Torah properly — with Chochma uMusar 1 p. 351 noting that the wisest person is the one who unites careful halachic study with contemplation of mussar, as the verse states, 'to know wisdom and mussar.'
The Tanya converges on this from its own angle: Tanya, Likkutei Amarim 42 insists that the essence of daat is not merely knowing God's greatness from books, but immersing one's mind deeply in that greatness and fixing one's thought on God with all the strength and vigor of heart and mind until the thought is bound to God as firmly as thought is bound to a material thing seen with physical eyes — and Tanya, Likkutei Amarim 3 explains the mechanism, that chochmah and binah, when the intellect genuinely contemplates and deepens, give birth to love of God and fear of God as their offspring.
Shiurei Daas 1 p. 15 captures the upward trajectory of the entire corpus: since a person can discover the Torah's rational principles within his own inner self through contemplation, he can thereby elevate himself through intellectual understanding of the Torah to attain its finest and deepest revealed concepts, and from these to reach the Torah's hidden secrets.