1. They Are the First 10 Days of the Jewish Year

The first 10 days of the month of Tishrei are known as the Aseret Yemi Teshuvah, the Ten Days of Repentance. It’s a period dedicated to repairing our connection with both G‑d and our peers, and restoring our souls to their pristine state.

Read: The 10 Days of Repentance

2. They Start With Rosh Hashanah and End With Yom Kippur

The 10 days are framed on either side with festivals—starting with Rosh Hashanah (when we crown G‑d as King) and ending with Yom Kippur (when we repair our relationship with G‑d and our fellow humans). The in-between days are not holy (you can work, travel, pay your bills), and yet, they’re not “mundane” or “ordinary” days either.

Read: 17 Rosh Hashanah Facts | 19 Yom Kippur Facts

3. They Are Mentioned in the Talmud

“Seek the L-rd where He is found; call to Him when He is near,”1 we read in Isaiah. The Talmud2 explains that the verse refers to the 10 days between Rosh Hashanah and Yom Kippur. It’s hard to pinpoint precisely when and how this period became known as “The 10 Days of Repentance,” but some of the earliest sources to use it are the Jerusalem Talmud3 and the Zohar.4

Read: 21 Talmud Facts

4.The Prayer Service Is Modified During These Days

One of the unique aspects of the Aseret Yemei Teshuvah is that we add or modify several of our prayers during these days. Specifically:5

  • We say Psalm 130 after the Pesukei D’zimrah (Verses of Praise) in the morning prayers.
  • We add several phrases to the Amidah prayers:
    • “Remember us for life … ”
    • “Who is like You … ?”
    • “Inscribe for good life … ”
    • “And in the book of life … ”
  • We change the conclusion of the Amidah prayer from “the Holy G‑d” to “the Holy King.”
  • In the Amidah blessing beginning with “Restore our judges,” we change the conclusion from “King Who loves righteousness and judgment” to “the King of judgment.”
  • We change the word “peace” at the very end of the Amidah to “the peace.”
  • We add the Avinu Malkeinu prayer to both the morning and afternoon prayers.
  • We continue saying Psalm 27 in both the morning and afternoon prayers.
  • Many communities have the custom to say special Selichot prayers during this time. The Chabad custom, however, is to not say them (aside from on Tzom Gedaliah).6 Read why here.

See here for more on the topic of prayer.

5. It Is a Time to Repair Mistakes

The Shulchan Aruch7 emphasizes that this is a time to repent for all misdeeds, especially ones we’ve excused ourselves for, like mistakes.

Here’s why: Judaism teaches that the soul is eternal.8 Before coming into this world, the soul was pure and holy, basking in G‑d’s presence. Coming into this world roughed it up a little bit; our mistakes and misbehaviors marred its once pristine beauty. Our true state and identity was and is our connection to G‑d. The noise and distractions of this world make us forget who we really are. But our soul doesn’t forget. And the further we distance ourselves from our true identity and purpose, the more our soul yearns to return. Teshuvah is that return.

Read: Where Is Life’s Undo Function?

6. They Include Two of the Six Annual Fast Days

That’s right: a third of the year’s fast days take place in just the first 10 days of Tishrei. In addition to Yom Kippur, there is is Tzom Gedaliah, which takes place on the 3rd of Tishrei (except when it coincides with Shabbat) and commemorates the assassination of Gedaliah ben Achikam (the governor of those Jews remaining in Israel after the destruction of the First Temple) and the events that followed.

Read: Jewish Fast Days FAQ

7. They Include a Special Shabbat, Shabbat Shuvah

Since there are seven days between Rosh Hashanah and Yom Kippur, the Ten Days of Repentance always includes a Shabbat. It is commonly known as Shabbat Shuvah, thus named for the day’s Haftarah, which begins with the words “Shuvah Yisrael” (“Return, Israel”). It is also called “Shabbat Teshuvah,” for the teshuvah we do during that Shabbat.

In many communities, the rabbi gives a special speech on Shabbat Shuvah, arousing the community to do teshuvah.

The Rebbe taught that the teshuvah of Shabbat Shuva is the highest level of teshuvah possible.9 On this plane, teshuvah is no longer about returning to your spiritual state before you came into this world, but surpassing it. In fact, the teshuvah of this Shabbat is the highest of the whole year—even higher than that of Rosh Hashanah10 and, in some ways, Yom Kippur.11

Read: Shabbat Shuvah

8. Rosh Hashanah and Yom Kippur are Both Counted and Not Counted

When counting the days of the Ten Days of Teshuvah, the Talmud seems to engage in some confusing mathematics. They refer to “ten days,” but clarify that those ten days are “between Rosh Hashanah and Yom Kippur.” But there are only seven days between Rosh Hashanah and Yom Kippur.

The Rebbe explains12 that this phraseology indicates that Rosh Hashanah and Yom Kippur both share in the overall theme of the Aseret Yemei Teshuvah (specifically, that they’re a time for repentance) and also have their own themes, distinct from both each other and the other seven days.

Read: 7 Days or 10 Days?

9. It’s a Time to Refocus

Rabbeinu Yonah Gerondi writes regarding the Ten Days of Repentance: “It is fitting for anyone who fears G‑d to reduce his affairs, so that his mind is relaxed, and to fix times during the day and night to seclude himself in his rooms and examine his ways, to rise early [for prayer], and occupy himself with the ways of repentance and the refinement of action, and to pour out speech, raise prayer and song and to lay down supplication.”13

Read: How the 10 Days Are Observed

10. Our Prayers Are More Easily Accepted

Though we can always pray to G‑d, our prayers are more readily accepted when we pray with a congregation (minyan). During this time of year, the prayers of an individual are more easily accepted.14 Chassidus explains that during these 10 days, we get in touch with our innermost core—known as our yechidah—and therein find the strength to change and elevate every aspect of our psyche.15

11. People Are More Careful About the Bread They Eat

Some background: Pat Yisrael (literally “Jewish bread”) refers to bread baked by a Jew. According to Jewish law, one must only eat bread that was baked (at least in part) by a Jew. Some people, however, are lenient with kosher-certified bread that was baked by non-Jews in a non-Jewish bakery. However, even they are stringent and eat only bona fide pat Yisrael during this time of year.16

Read: 22 Kosher Facts

12. We Avoid Certain Court Activities on These Days

Because we are endeavoring to arouse G‑d’s mercy, we avoid certain activities. For example, we don’t issue a cherem (a ban of excommunication), and we don’t make someone take an oath to prove they’re not lying.

We should, however, engage in cases that involve removing objects wrongfully in the possession of a definite liar, as long as they don’t require someone to take an oath.17

Read: What Is a Jewish Court?

13. It Is Not the Only Time We Can Do Teshuvah

Just because these 10 days are called the Ten Days of Teshuvah doesn’t mean they’re the only time we can do teshuvah. In fact, the Sages teach that teshuvah can be instantaneous,18 and that nothing stands before teshuvah.19 Teshuvah is therefore always appropriate and always the right choice.

Read: Teshuvah: The Art of Return

14. There Is a Day for Every Day of the Week

Rabbi Chaim Vital writes in the name of the AriZal that the week between Rosh Hashanah and Yom Kippur has the power to repair all the weeks of the previous year.20 Meaning, doing teshuvah on the Monday of the Ten Days repairs all the Mondays of the past year, doing teshuvah on the Tuesday fixes all the Tuesdays, and so on.

15. G‑d Lifts Us Higher Than We Can Lift Ourselves

Chassidic thought points to two ways growth in our relationship with G‑d can be initiated: either we initiate the growth or G‑d does.21 Each has its own advantage. When we initiate, it comes from our own hard work; when G‑d initiates, the growth is on a level higher than we could have achieved on our own (like a parent lifting a child higher than they could have reached on their own).

The Aseret Yemei Teshuvah is a period of G‑d initiating.22 The overwhelming awe and significance of these days offer us the opportunity to connect to our Creator on a greater level than we can during any other time of the year. We just have to seize the opportunity.

16. They Are Followed by Sukkot and Simchat Torah

The Ten Days of Teshuvah are just the first 10 days of Tishrei. Five days later, on Tishrei 15, we begin the joyous holidays of Sukkot and Simchat Torah.

Read: 13 Sukkot Facts | 15 Simchat Torah Facts