Shabbat 105B

דעבדה כי כיסתא.

The Talmud explains: It is found in a case where a pocketlike protrusion impedes sewing. Therefore, one tears the garment and tucks the protruding portion under the seam.

מתני׳ הקורע בחמתו ועל מתו, וכל המקלקלין ⁠— פטורין. והמקלקל על מנת לתקן ⁠— שיעורו כמתקן. שיעור המלבן והמנפץ והצובע והטווה ⁠— כמלא רחב הסיט כפול, והאורג שני חוטין ⁠— שיעורו כמלא הסיט.

Mishnah: One who rends his garment in his anger or in anguish over his dead relative is exempt. And anyone else who performs labors destructively on Shabbat is exempt. And one who performs a labor destructively in order to repair is liable, and his measure for liability is equivalent to the measure for one who performs that labor constructively. The measure that determines liability for one who whitens, or one who combs, or one who dyes, or one who spins wool is the full width of a double sit, which is the distance between the forefinger and the middle finger. And for one who weaves two threads, the measure that determines liability is one sit.

גמ׳ ורמינהו: הקורע בחמתו ובאבלו ועל מתו ⁠— חייב, ואף על פי שמחלל את השבת, יצא ידי קריעה! לא קשיא: הא במת דידיה, הא במת דעלמא.

Talmud: We learned in the Mishnah: One who rends his garment in anger or in anguish over his dead relative is exempt. The Talmud raises a contradiction to this based on a baraita: One who rends his garment in his anger or in his mourning or in his anguish over his dead relative is liable for performing a prohibited labor on Shabbat. And even though he desecrates Shabbat by tearing his garment, he nevertheless fulfilled his obligation of rending his garment in mourning. Apparently, one is liable for rending his garment in anguish over the dead. The Talmud answers: This is not difficult, as this Mishnah, which states one is liable for rending his garment, is referring to his own dead relative for whom he is obligated to tear his garment. And that Mishnah, which states one is exempt for rending his garment, is referring to any unrelated dead person.