Commentary for Shabbat 50:3
רבי ישמעאל אומר כו': מאי טעמא אמר רבא מתוך שריחו רע גזרה שמא יניחנה ויצא אמר ליה אביי ויצא אמר ליה שאני אומר הדלקת נר בשבת חובה דאמר רב נחמן בר רב זבדא ואמרי לה אמר רב נחמן בר רבא אמר רב הדלקת נר בשבת חובה רחיצת ידים ורגלים בחמין ערבית רשות ואני אומר מצוה
How is it a mizwah? For Rab Judah said in Rab's name: This was the practice of R. Judah b. Il'ai: On the eve of the Sabbath a basin filled with hot water was brought to him, and he washed his face, hands, and feet, and he wrapped himself and sat in fringed linen robes,<span class="x" onmousemove="('comment',' The fringes were of wool. This constitutes a forbidden mixture (v. Deut. XXII, 11), and it is disputed by Tannaim whether this should be done. ');"><sup>7</sup></span> and was like an angel of the Lord of Hosts. But his disciples hid the corners of their garments from him.<span class="x" onmousemove="('comment',' Because they were not provided with fringes, V. next note. ');"><sup>8</sup></span> Said he to them, My sons! Have I not thus taught you: A linen robe, in respect to fringes-Beth Shammai exempt it, while Beth Hillel hold it liable, and the <i>halachah</i> is as Beth Hillel? But they held, It is forbidden on account of a night garment.<span class="x" onmousemove="('comment',' A garment worn only at night is not subject to fringes; consequently, this forbidden mixture (v. n. 3) is then forbidden, since there is no precept of fringes to supersede it. The disciple held that Beth Hillel's ruling was Scriptural only; nevertheless it is forbidden by Rabbinical law, to avoid confusing night attire with day attire. ');"><sup>9</sup></span>