הַמַּחֲשָׁבָה הִיא לְבוּשׁ וּמְשָׁרֵת הַשֵּׂכֶל וְהַמִּדּוֹת. בְּשָׁעָה אֲשֶׁר אֵין לָהּ שֵׁרוּת בְּשֵׂכֶל אוֹ בְּמִדּוֹת, גַּם אָז פּוֹעֶלֶת פְּעוּלָתָהּ לַחֲשׁוֹב וּלְהַרְהֵר, אֲבָל פְּעוּלָתָהּ לֹא לְבַד שֶׁאֵינָה תּוֹכְנִית, אֶלָּא הִיא גַּם פְּרוּעָה לְשִׁמְצָה... וּמְבוּאָר כִּי סִבַּת הַמַּחֲשָׁבוֹת זָרוֹת אוֹ רָעוֹת הוּא דִי פּוּסטקַייט פוּן קאָפּ, דְּכַאֲשֶׁר הַשֵּׂכֶל עָסוּק אָז יֵשׁ לְהַמַחֲשָׁבָה מַה לְשָׁרֵת וְאֵין מָקוֹם לְמַחֲשָׁבוֹת שֶׁל שְׁטוּת וְהֶבֶל שֶׁאֵין בָּהֶם מַמָּשׁ.

Thought is a garment and a servant for the mind and the emotions. When it is not assigned a task by the mind or the emotions, it still remains active, thinking and imagining. However, not only does this activity lack substance, it is uncontrolled and decadent....

As is explained elsewhere, the cause of alien thoughts (machshavos zaros) and evil thoughts (machshavos ra’os) is an empty mind. When one’s mind is busy, thought has a purpose to serve, and there is no place for foolish and worthless thoughts that lack substance.1

Probing Beneath the Surface

Our minds are always working. It is our task to show them what to work on.

One of the visible and immediate rewards of diligent Torah study is that it furnishes our minds with something positive to focus on at all times. Moreover, the Torah we have studied monitors and changes the nature of our thoughts. As with a computer, once a given program is installed, all the other information it is fed is interpreted according to that program.

Hence, instead of spending a lifetime trying to fight off negative thoughts, a chassid habituates himself to occupy his mind with pure thoughts, Torah thoughts — luminous thoughts. After all, as the Rebbe Rayatz used to say, “Darkness you don’t drive away with a stick.”2