Salmi 111:10 Cabala: Zohar & Or Neerav

Rabbi Aba said, "Serve Hashem in fear" 1. What fear is meant here? As we have established, it is written, "The fear of Hashem is the beginning of knowledge" (Mishlei 1:7) and "the fear of Hashem is the beginning of wisdom" (Tehilim 111:10), so the Holy One, blessed be He, is referred to in this name, "Fear of Hashem," Rabbi Elazar said: "Serve Hashem in fear," he who wishes to perform the service of his Master, from what point should he begin and to which area should he aim his service in order to unify the name of his Master? He repeats his words "with fear," because fear (which corresponds to Malchut) is the start (of service) going from below upwards.

Reshit Ḥokhmah (“Beginning of Wisdom” [Ps. 111:10]). Malkhut.

בְּרֵאשִׁית. Rabbi Chiya opened the discussion with the verse, "The fear of Hashem is the beginning of wisdom; good understanding have all they who do His commandments; His praise endures forever" (Ps. 111:10). Of the phrase, "the beginning of wisdom," this verse have read 'the fear of Hashem is the end of wisdom,' because the fear of Hashem (is the secret of Malchut), which is at the end of Chochmah! She (Malchut) is the beginning or the first stage that opens the entrance to the level of the supernal Chochmah (Wisdom). So it is written, "Open to me the gates of righteousness" (Ibid. 118:19), "this is the gate to Hashem" (Ibid. 20). Assuredly, if he does not enter this gate, he shall never reach the Supernal King, because He is exalted, hidden, and concealed, and has made gates for Himself, one behind the other.