The Sages instituted an extra prayer service near the end of the fast, for all who increase their prayers will be answered. If we have not managed to be answered through the regular prayers, perhaps an additional prayer will be answered. This service is referred to as Ne’ila because it is recited at the time when the gates of the Sanctuary were locked (ne’ulim) at the conclusion of the day’s avoda. The “locking of the gates” also corresponds to the closing of the gates of heaven. For at the end of the day, the sanctity of Yom Kippur recedes, and the gates of heaven, which were open to those who knocked through repentance, are locked.
The time of Ne’ila is when the sun can be seen in the treetops in the west, approximately forty minutes before sunset. Those who wish to begin as much as an hour before sunset may do so. The ḥazan must time his prayers so that Birkat Kohanim can be completed before sunset (as explained in the previous section).
Even though the gates of the Sanctuary were locked at sunset, the gates of heaven are locked only at the end of the day, after all light has vanished. Therefore, we continue reciting prayers and supplications until tzeit. A ḥazan who extends Ne’ila past tzeit is not to be reprimanded.
The Ne’ila prayers differ from all other prayers recited during the Days of Awe; wherever we ask to be “inscribed” for good, we now ask to be “sealed,” because now, at the end of Yom Kippur, our verdicts are being sealed. Nevertheless, someone who accidentally invoked “inscribing” instead of “sealing” need not repeat the prayer.
One should marshal all his strength for Ne’ila, for Yom Kippur is the culmination of the Ten Days of Repentance, and Ne’ila is the culmination of Yom Kippur. Everything leads up to the final verdict, so if not now, when? Therefore, even someone who is weak from fasting should summon his strength to pray with clear and pure focus, to resolve to repent and to increase his Torah study and mitzva observance (MB 623:3). Because Ne’ila is so important, it is customary to leave the ark open from the beginning of the repetition of the Amida until the Kaddish at the conclusion of the service (Mateh Ephraim 623:7).
The Yerushalmi explains that according to Rav, Ne’ila refers to the locking of the gates of heaven and may be recited until dark. Moreover, according to Rav, one who recited Ne’ila need not recite Ma’ariv (Yoma 87b). According to R. Yoḥanan, though, Ne’ila refers to the locking of the gates of the Sanctuary and may be recited only until shki’a (y. Berakhot 4:1). Most understand this to be because he maintains that one may recite Ne’ila at night. In practice, some rule in accordance with Rav that Ne’ila may recited until night (Roke’aḥ, Or Zaru’a, and Raavya), while many others rule in accordance with R. Yoḥanan and limit the time to shki’a (R. Ḥananel, R. Yitzḥak ibn Gi’at, Rambam, Maharam of Rothenburg, Ritva, and Mordekhai). This is also the ruling of SA 623:2. Nevertheless, we do not object to a ḥazan who extends the repetition of the Amida of Ne’ila past tzeit, as he has an opinion on which to rely (MB ad loc. 2). See 6:3 n. 1 above, about how Ne’ila completes the atonement of Yom Kippur.