he Rebbe advises not to fight or engage with negative thoughts, but to redirect the mind to Torah. He recommends daily Torah, Tanya, Tehillim, and Mishnah study, giving tzedakah, guarding one’s eyes, and strengthening bitachon. He stresses avoiding sadness even after failure and encourages learning Tanya for deeper guidance.
https://www.torahrecordings.com/rebbe/igroskodesh/015/012/5674