Halakhah sa Mga Kawikaan 23:21: Mishneh Torah, Torah Study & Shulchan Arukh, Yoreh De'ah

It is not permitted to sleep in the Beth Hamedrash, and whosoever drowses in the Beth Hamedrash, his wisdom becomes torn rags; for even so Solomon in his wisdom said: "And drowsiness shall clothe a man with rags" (Prov. 23. 21). No conversation is permitted in the Beth Hamedrash save in words of Torah. Even one who sneezed, it is not said to him: "May it be a cure to you," in the Beth Hamedrash; needless to mention other kind of conversation. The sacredness of the Beth Hamedrash is of greater force than the sacredness of synagogues.⁹Megillah, 28a; Ibid. 26b; Abodah Zarah, 71b; Sukkah, 28a; Sanhedrin, 70b; Berakot, 23b. C. G.

One should not sleep in the study hall. Anyone who dozes in the study hall, his wisdom becomes torn into pieces, as it says, "Slumber will clothe one in rags" (Proverbs 23:21).