And a man must conceal a secret which his friend tells him in private, even though there is no rechiluth in the revelation of this secret. For there is in its revelation harm to its confider and cause for voidance of his plans. Also, in this ["dust" of rechiluth], he departs from the way of modesty and transgresses the will of his confidant.
(ז) וְחַיָּב אָדָם לְהַסְתִּיר הַסוֹד, אֲשֶׁר יְגַלֶּה לוֹ חֲבֵרוֹ דֶּרֶךְ סֵתֶר, אַף עַל פִּי שֶׁאֵין בְּגִלּוּי הַסוֹד הַהוּא עִנְיַן רְכִילוּת, כִּי יֵשׁ בְּגִלּוּי הַסוֹד נֵזֶק לִבְעָלָיו וְסִבָּה לְהָפֵר מַחֲשַׁבְתּוֹ, גַּם בָּזֶה הוּא יוֹצֵא מִדֶּרֶךְ הַצְּנִיעוּת, וְהוּא מַעֲבִיר עַל דַּעַת בַּעַל הַסּוֹד.
And a man must conceal a secret which his friend tells him in private, even though there is no rechiluth in the revelation of this secret. For there is in its revelation harm to its confider and cause for voidance of his plans. Also, in this ["dust" of rechiluth], he departs from the way of modesty and transgresses the will of his confidant.