Based on the perfect record of the Spring Festivals all fulfilled at the First Coming of Yeshua, the Fall Feasts will be fulfilled at the Second Coming of Yeshua the Messiah:
• Rosh Hashanah: Leviticus 23:23-25 - The Regathering of the Saints (Isaiah 27:12-13 - 1 Thessalonians 4:13-18;  1 Corinthians. 15:15-58)
• Yom Kippur: Leviticus 23:26-32 - The Great Tribulation (Ezekiel 36:24-25; Zechariah 13:8-9, 12:10, 2 Corinthians 5:10)
• Sukkot: Leviticus 23:33-44 - The Ingathering of the Messiah and the Believers (John 7:38-39, 8:12; Zechariah 14:16-19; Matthew 17:4)

The order is very important. Keeping in mind that calendar events repeat each year in the same order, Rosh Hashanah always occurs ten days before Yom Kippur, which happens a few days prior to Sukkot. There are good reasons to connect Rosh Hashanah or Yom Teruah (The Day of Trumpets) with the Rapture of the Body of Messiah–if not by date, at the very least, thematically. Logically, Yom Kippur would connect with the next event on God's program, and that is the Time of Jacob's Trouble or Great Tribulation, also known as Daniel's 70th week (Daniel 9:27.)

Yom Kippur is a very solemn day on the Jewish calendar. It is a holy day but not a feast. It is a fast of one day when Jewish people reflect at home or in the synagogue. No comfortable clothes are worn, no perfume, and no food. Of course, we have come a long way from the strict regimen that the High Priest had to undergo in biblical times (Leviticus 16,) but the date is taken very seriously by contemporary rabbis.

It is believed that on Yom Kippur, God opens three books in heaven: The Book of the "Wicked," the Book of the "In-Between," and the Book of the "Righteous." Obviously, nobody cares to be listed in the Book of the "Wicked," and nobody is arrogant enough to claim belonging to the Book of the "Righteous." That leaves just about every religious Jew praying that their name will be listed in the Book of the "In-Between" for the next year until the following Yom Kippur.
Toward that goal, religious Jews are given a period of ten days between Rosh Hashanah and Yom Kippur, known as Yamin Moraim or the "Days of Awe." This Rabbinic addition to the Jewish calendar has only one purpose: giving a Jewish person the opportunity to make amends, ask for forgiveness or apologize for wrongdoing or wrong saying, placing them in good standing with God right before He decides to place their name in one of the three books.

This is based on the basic rabbinic principle that man can atone for his own sins through works. But can one truly go back to all the people they hurt? Does God consider the best effort? This seems to be a stressful predicament that Jewish people find themselves into, unless of course, they consider that Yeshua the Messiah paid the price for their shortcomings once and for all, over 2,000 years ago. Then, there is no need for any guesswork on the writing of our names because the Bible tells us that once we place our trust in the death and resurrection of Yeshua the Messiah (Isaiah 52:13-53:12), our name is written forever in the Lamb's Book of Life ( Revelation 20:15; 21:27.)

But beyond the Jewish traditions attached to Yom Kippur, we must consider the grave prophetic implication of that Holy Day. One of three key scriptures for Yom Kippur, along with Leviticus 16:1-34 and Numbers 29:7-11, is Leviticus 23:26-32 where, among other details, we are told that Jewish people are to humble themselves. It is to be a solemn day to humble or afflict the soul. So, along that theme, Yom Kippur is also a day of repentance based on Ezekiel 33:19: "But when the wicked turns from his wickedness and practices justice and righteousness, he will live by them."

The word kippur comes from the Hebrew kaphar meaning “to cover.” It is found 110 times in the Tenach, mostly in Leviticus and Numbers. The word is not found in the New Testament. While the sacrificial system covered individual sins, Yom Kippur covered national sins, but it was only applied to the individual who afflicted his soul (Leviticus 23.) Yom Kippur will be fulfilled by the Great Tribulation, also known as the Time of Jacob's Trouble and Israel’s national Atonement in the Tribulation (Ezekiel 20:33-38; Hosea 5:15-6:3; Zechariah 12:10-13:1)

Hosea 5:15 speaks of the physical affliction of Israel, while Hosea 6:1-3 speaks of the spiritual affliction of Israel.

One tragic aspect of the Great Tribulation, seen as God resuming His divine program about Israel, is found in Zechariah 13:8-9: "And it will come about in all the land,” Declares the Lord, That two parts in it will be cut off and perish; But the third will be left in it. ⁹ And I will bring the third part through the fire, Refine them as silver is refined, And test them as gold is tested. They will call on My name, And I will answer them; I will say, ‘they are My people,’ And they will say, ‘The Lord is my God.’”

Sadly, it appears that two-thirds of the Jewish people will perish during the Great Tribulation. If this were to happen today, 10,000,000 Jewish people would die, and that would be almost twice Hitler's Holocaust. Taking a closer look at that passage, we notice that the verses speak of a percentage and NOT an exact number. All throughout the Bible, God is very precise when He wants to be, and He will not hesitate to give us exact numbers. So, what are we to do with a percentage? Well, rejoice and get busy!

As a pre-tribulational, pre-millennial believer, I believe in a literal Rapture of the believers that will occur before the Great Tribulation takes place. Anyone who has believed that Yeshua is the Messiah of Israel and Savior of the world from Acts 2 forward will be taken in the Rapture, and that includes Jewish people who become believers in the Messiah. So, the more Jewish people come to Yeshua before the Rapture, the less will have to endure the Great Tribulation. The percentage of 2/3 and 1/3 will always be the same, but it is up to us to boldly proclaim the Gospel to our Jewish friends and reduce the numbers contained within the percentages.

Incidentally, the 1/3 that is "refined as silver and tested as gold" will become believers at the end of the seven years as, according to Zechariah 12:10, they proclaim Baruch Haba Bashem Adonai! So, Yom Kippur has a great fulfillment for the world in general and for the Jewish people in particular. It ushers in the return of Yeshua on earth, in Jerusalem, to inaugurate the Messianic or Millennial kingdom. Yeshua will not return until the remnant of Jewish people call on Him at the end of the Tribulation.

Rosh Hashanah will be fulfilled by the Rapture. (No, it is not necessary that the Rapture happens on Rosh Hashanah for the event to fulfill the Feast.)
Yom Kippur will be fulfilled by the Great Tribulation and the chastising of Israel, bringing the 1/3 to salvation and ushering in the return of Yeshua. It all makes sense in that order. Then, if you consider the perfect correlation between the Feast of Tabernacles and the Millenial Kingdom (Leviticus 23:33-43; Exodus 23:14-17; John 7:38-39, 8:12; Zechariah 14:16-19),  you quickly realize that it is all part of God's plan for the ages and it is simply perfect!