Why the Extra Ne'ilah Service on Yom Kippur?

Yom Kippur is not only a day of fasting, atonement, and introspection. It is a day for a whole lot of religious services. On normal days, there are Shacharit, Mincha, Ma'ariv. On Shabbat and the holidays, there is the extra Mussaf service. But with Yom Kippur, there is an extra service on top of Shabbat: Ne'ilah (נעילה). Literally meaning "locking," Ne'ilah comes at the end of Yom Kippur. Why do we need an extra service at the end? I know that there is not much to do on Yom Kippur aside from praying, but I would like think there is more to the Ne'ilah service than having us kill time at the end of services because "there's nothing better to do." So what is the significance of Ne'ilah?

For many traditional Jews, the Ne'ilah service is about having one last chance to repent for what one has done in the previous year. Through G-d's mercy do we get an extra opportunity to do teshuvah. A verse that makes its way into the Ne'ilah service is Isaiah 43:25, "I, just I, am He who wipes your transgressions. For my own sake, I will not remember." This notion is in alignment of the traditional understanding of the Hebrew word נעילה, which has referred to one of two things (Jerusalem Talmud, Berakhot 4:1).

One is that it refers to the locking or closing of the Heavenly Gates. That argument falls short since the Gate of Tears is never closed. The second closing could correspond to the closing of the Temple, but as R. Arthur Green brings up in Yom Kippur Readings, that correspondence is not impressive. It would be more accurate to say that what is closing is our hearts. The High Holy Day season takes a lot out of us emotionally. According to R. Green, Ne'ilah is that time where we realize that we move from supplication to making peace.

What we can glean from R. Green's interpretation is that Ne'ilah is not just about what we have done, but also about the potential we can achieve in the upcoming year. I think the forward-looking focus is another way of looking at this service for three reasons:

1. Going back to the Isaiah 43:25, the following verse (43:26) gives us some context. G-d is asking that we "reason together" (נשפטה יחד) in order that we may be justified (למען תצדק). According to this interpretation, G-d does not just want us to be penitent for our wrongs, but also ask how to make things right. Per these passages from Isaiah in the context of the Ne'ilah service, it is a reminder that G-d wants to forgive us. If G-d is capable of forgiving us, shouldn't we also be able to forgive ourselves? When we reach that stage, we can better move forward. 
2. R. Yisrael Salanter pointed out that most people do teshuvah on the High Holy Days, while the more pious do so on the month of Elul. R. Salanter went as far as saying that we should do teshuvah right after Ne'ilah services are over. R. Salanter's main point was that teshuvah is a year-round endeavor. To take R. Salanter's words a step further, Ne'ilah is supposed to be that extra push that gets us going in moving forward for the upcoming year. 
3. In each of the Yom Kippur services is a Viduy (וידוי), a confession. In the Ne'ilah service, we read through the Ashamnu. However, unlike the other services, the Ne'ilah Viduy does not have an "Al Chet," the longer confession within the Viduy that mentions specific sins. The "Al Chet" is replaced with two new paragraphs: "Atah noten (אתה נותן)" and "Atah hidalvta (אתה הבדלת)." Within these two paragraphs, the only specific sin mentioned is theft. My rabbi, R. Shmuel Herzfeld, mentions this in his book Food for the Spirit. Why, according to my rabbi, is theft the only specific sin mentioned? As R. Joseph Soloveitchik explained, every sin we commit is really a sort of theft against G-d. When we err, we violate our purpose on earth. R. Herzfeld expounds upon this by saying that when we steal from G-d, we have lost our focus and forgot why we are here. We read this passage to remind us about our responsibility in this world and what we are meant to do (Herzfeld, p. 92). Reciting this towards the end of Ne'ilah is meant to bring our focus on what is to come. 

The Ne'ilah service is important because it is that segue between the High Holidays period and the New Year. It is what connects our past to our future. Yes, we are meant to look back and make up for our shortcomings. However, looking back only does so much good if we do not take it in the context of looking forward. Amend for past mistakes to be sure, but also learn from those mistakes to propel yourself forward. As R. Jonathan Sacks brings up in his Yom Kippur machzor, Ne'ilah is not about asking "Are you perfect?" but "Can you grow?" That is what Ne'ilah is about: take that lesson and be the best version of you that you can be!