Daf 71b (דַּף ע״א ע״ב)

And these are the matters of hair that is smooth and glossy between the eyes (וְהָנֵי מִילֵּי שַׂעֲרָא דְּמָרִיט בֵּין עֵינוֹי), above the brain (עַל גַּבֵּי מוֹחָא), in the place where Tefillin are laid (בַּאֲתַר דְּאָנַח תְּפִלִּין). But if it is in another part of the head (וְאִי בַּאֲתַר אַחֲרָא דְּרִישָׁא), it is not so (לָאו הָכִי). He is not a deceiver (וְלָאו אִיהוּ רַמָּאָה), but a master of an evil tongue (אֶלָּא מָארֵיהּ דְּלִישָׁנָא בִּישָׁא), whispering without projection of voice (בִּלְחִישׁוּ, בְּלָא אֲרָמוּת קָלָא). At times he fears sin (לְזִמְנִין דָּחִיל חַטָּאָה אִיהוּ), and at times he does not (לְזִמְנִין לָא). And this is in the secret of the letter Zayin (וְדָא אִיהוּ בְּרָזָא דְּאָת ז׳), when it is crowned with the letter Yod (כַּד כָּלִיל אָת י׳). Up to here are the secrets of hair for masters of discernment (עַד הָכָא רָזִין דְּשַׂעֲרָא לְמָרֵי מִדִּין), who know the paths and mysteries of the Orayta (דְּיַדְעֵי אָרְחֵי וְרָזֵי דְּאוֹרַיְּיתָא), to perceive the hiddenness of human beings (לְאִשְׁתְּמוֹדְעָא טְמִירוּ דִּבְנֵי נָשָׁא), who are in the image of Elohim, with the concealed Name (דְּאִינּוּן בְּצֶלֶם אֱלֹהִים סָתוּם שְׁמָא), which branches out into many paths (דְּאִתְפְּרַשׁ לְכַמָּה אָרְחִין).

In the secret of the forehead is the letter Nun (בְּרָזָא דְּמִצְחָא, בְּאָת נ׳), which is the completion of the letter Zayin (דְּאִיהוּ שְׁלִימוּ דְּאָת זַיִ״ן). At times it is included in the secret of Zayin (לְזִמְנִין אִתְכְּלִילַת בְּרָזָא דְּאָת ז׳), and at times it stands alone (וּלְזִמְנִין אִיהוּ בִּלְחוֹדָהָא). A forehead that is narrow and sharp, without curvature (מִצְחָא דְּאִיהוּ דָּקִיק וְחַד, בְּלָא עִגּוּלָא) this is a man who cannot settle his thoughts (דָּא הוּא בַּר נָשׁ דְּלָא מִתְיַישְׁבָא בְּדַעְתֵּיהּ). He thinks himself wise, but does not know (חָשִׁיב דְּאִיהוּ חַכִּים, וְלא יָדַע). He is agitated in spirit (אִתְבְּהִיל בְּרוּחֵיהּ). He smiled (Some say: he bites) with his tongue like a serpent (חֲיִּיךְ [ס״א: נָשִׁיךְ] בְּלִישָׁנֵיהּ כְּחִוְיָא).

If the furrows of his forehead are wide (קְמִיטִין דְּמִצְחֵיהּ רַבְרְבָן), and they are not in alignment (וְלָאו אִינּוּן בְּזִוּוּגָא), and when he speaks they become visible (בְּשַׁעֲתָא דְּמַלִּיל אִתְעָבִידוּ אִינּוּן קְמִיטִין בְּמִצְחֵיהּ), but not in harmony (וְלָאו בְּזִוּוּגָא) other markings on his forehead are all in union (רְשִׁימִין אַחֲרָנִין דִּי בְּמִצְחֵיהּ כֻּלְּהוּ בְּזִוּוּגָא). This is one who should not be bonded with long-term (דָּא, בָּעֵי דְּלָא לְאִזְדַּוְּוגָא לֵיהּ), but only for a short time (אֶלָּא זִמְנָא זְעֵירָא), and not for an extended period (וְלָא זִמְנָא סַגִּי). Everything he does and thinks is for his own benefit (כָּל מַה דְּעָבַד וְחָשַׁב, אִיהוּ לְתוֹעַלְתֵּיהּ), and he does not care for others' benefit (וְלָא חָיִישׁ לְתוֹעַלְתָּא דְּאַחֲרָנִין). He is not a master of secrets at all (לָאו אִיהוּ מָארֵי דְּרָזִין כְּלָל). This is what is written: “He who goes about as a talebearer reveals secrets” (Proverbs 11) (דָּא אִיהוּ, הוֹלֵךְ רָכִיל מְגַלֶּה סּוֹד), and his words are of no weight (וְלָא חָשִׁיב מִלּוֹי כְּלָל). This is in the Secret of the letter Nun included within the Zayin (דָּא אִיהוּ בְּרָזָא דְּאָת נ׳ דִּכְלִילָא בְּאָת ז׳), but he is not called “a faithful spirit in continuity” (וְלָא אִקְרֵי נֶאֱמָן רוּחַ בְּקִיּוּמָא).

A forehead that is narrow and rounded (מִצְחָא דָּקִיק בְּעִגּוּלָא) this is a wise man (דָּא אִיהוּ בַּר נָשׁ חַכִּימָא), in what he contemplates (בְּמָה דְּאִסְתָּכַּל). At times his spirit is shaken (לְזִמְנִין אִתְבְּהִיל בְּרוּחֵיהּ). His affection is with joy (רְחִימוּ דִּילֵיהּ בְּחֶדְוָה). He is compassionate to all (רַחֲמָן אִיהוּ עַל כֹּלָּא). He contemplates many matters (אִסְתָּכַּל בְּמִלִּין סַגִּיאִין). If he labors in Orayta, he will become exceedingly wise (אִי יִשְׁתָּדַּל בְּאוֹרַיְּיתָא לֶהֱוֵי חַכִּים יַתִּיר).