Kabbalah Amsal 25:2: Kuntres Mattan Torah, Sha'arei Kedusha, Sefer HaBahir & Sha'arei Orah

At that time, even the knowledgeable had no interest in or were asked to author books of this kind, since this knowledge is unnecessary for the average person. On the contrary, it was in their interest to keep the matters hidden as “It is the glory of God to conceal a thing” (Proverbs 25:2) since we were commanded to hide the soul of the Torah and service from those who do not need it or do not merit it, so it would not be belittled or displayed for the interest of those who look at it through a peephole or the boastful, for we are beholden to the glory of God.

Our sages, of blessed memory, stated,⁵²¹Tanna d’Vei Eliyahu Rabba, Ch. 21; Also see Mishnah Avot 2:12 “A person should always be in a state of fear of Heaven, even in private, and all his ways should be for the sake of Heaven.” If a person is able, he should conduct himself in all his deeds and ways for the sake of Heaven, without revealing any of it to the creatures. His reward will be doubled and quadrupled, as the verse states,⁵²²Proverbs 25:2 “It is the honor of God to conceal a matter.”

[Mar Rachumai continued,] it was taught, ' It is the glory of Elohim to conceal a word' (Proverbs 25:2). What is 'a word'? As it is said, 'Truth is the essence of Your word' (Psalms 119:160) [and] 'The glory of kings is to examine a word' (Proverbs 25:2). What is 'a word'? As is written, 'A word spoken in its proper form [אופניו]' (Proverbs 25:11). Do not read 'proper form' [אופניו], rather, 'His faces' [אפניו]."