The Best Time of Night for Sleeping

The Kabbalists taught that it is preferable to sleep during the first part of the night – from nightfall (when the stars come out) until Hasot (halachic midnight). During this first half of the night, the Kabbalists explained, the harmful spiritual energies are in force, posing danger to the purity of the Neshama (soul). It is thus best to go to sleep right at nightfall, when these energies surface, as when one sleeps his soul is entrusted to Hashem and hence protected from these forces. Then, right before Hasot, one should rise and involve himself in Torah and prayer. This was the practice followed by the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909). Citing the Arizal, the Ben Ish Hai taught that the first part of the night of called "Layil," whereas the second part of the night is called "Layla." The exceptions to this rule are Friday night and the night of the Seder. On Friday night, the sanctity of Shabbat protects the soul from harm, and the night of the Seder is called "Lel Shimurim" (Shemot 12:42), a night of protection, when even the "Layil" portion of the night is safe for the soul due to the special quality of this night. However, Hacham Ovadia Yosef noted that both the Gemara (Berachot 62b) and the Rambam (Hilchot De'ot 4:4) instruct that sleep is most beneficial during the latter part of the night. Hacham Ovadia writes that he saw Rabbis in Jerusalem who followed the Ben Ish Hai's practice, but his practice was to learn until late at night and then go to sleep. Practically speaking, it seems that the advent of electric lighting and modern travel and communication has rendered this question moot. Years ago, there was no possibility of working or doing much else after dark, and so people stayed home. Today, of course, people are still busy after nightfall, and it is not practical for most people to go to sleep right at nightfall – which can be as early as 5:30pm or so in the winter – and then wake up at Hasot. Therefore, while there are those (such as the "Kollel Hasot" program) who sleep during the first part of the night and then rise before Hasot, for most people it is more proper to learn at night and then go to sleep.