I am an Orthodox Jew. Orthodox Judaism recognizes that Judaism today is Rabbinical Judaism. It is based on what is called the Oral Law, the rabbinical interpretation of the Bible. For example, the Oral Law teaches that “an eye for an eye” should not be taken literally; it means monetary compensation.


Rosh Hashanah is not a biblical holiday, although it replaced a biblical one. It is clearly different from the holiday it changed. The biblical holiday, Yom Teruah, was a one day festival that had totally other purposes than Rosh Hashanah that is celebrated for two days and focuses on the onset of a year, repentance, and commitment to live the next year properly, ideas not even suggested in Yom Teruah that concentrated on months and the number seven.


The Bible

Leviticus 23:23-25 and Numbers 29:1-6 describe the day that gave birth to Rosh Hashanah. It was Yom Teruah, also called Yom Zichron Teruah, the Day of Blowing the Horn and the Day of Memorial Proclaimed with the Blowing of the Horn.


The only mention of Rosh Hashanah, New Year, in the Bible is in the writing of the sixth century BCE prophet Ezekiel in 40:1. However, as indicated in the book Divrei Hayamim, Yechezkel, page 203, Ezekiel was not talking about the first day of the seventh month, later called Tishre, the date of the current holiday of Rosh Hashanah. Ezekiel spoke about the first day of the first month later called Nisan. (The names currently assigned to the Jewish months were given in the sixth century BCE during the Babylonian exile.)


According to the Torah, in Exodus 12:2, as recognized by Ezekiel, the beginning of the year is the month later called Nisan. This is the month in which the Israelites who were freed from Egyptian slavery became a nation. The New Year was celebrated in the spring by Passover and Hag Hamatzot, on the 14th for one day and the 15th of the first month for seven days. Spring is the natural beginning of the year. It is the time when the earth begins to produce fruits and vegetables. It was only during the Babylonian exile of 586 BCE that the Judeans accepted the Babylonian concept that the year starts in the fall, and the first day of the seventh month begins the year.


While there is no practical or religious need to identify the date of creation – and indeed, it is impossible to do so – Judeans began to believe during the exile that the world was created on the first day of Tishre. The Bible does not state the date when the world was created. In fact, if the six day events of creation are taken as six periods of time as indicated in the Babylonian Talmud, Ketubot 57b, which states yamim (days) can mean years, we can understand the Bible saying the creation was a long process with different events happening at other times, so there is no single day of creation. The Talmudic sages knew that we cannot pinpoint a day of creation; they even argued homiletically, and only homiletically, about whether the world was created in Nisan or Tishre in the Babylonian Talmud, Chagigah 12a, Rosh Hashana 8a, 10b-11a, 27a, and Avodah Zarah 8a.


How was Rosh Hashanah first celebrated?

On the first day of the seventh month around the fifth century BCE, shortly after the Babylonian exile, Ezra the Scribe, the leader of the Judeans at that time, gathered the people and read the Torah, or some of it, to them. According to the Biblical book Nehemiah 8:10, he said to them: “Go your way, eat rich viands, drink the sweet beverages, and send portions to him who has none prepared: for this day is holy to our Lord; do not be sad; for joy in the Lord is your refuge.” Ezra’s joyous description of how the Judeans should celebrate the first day of Tishre is in no way similar to how Rosh Hashanah is celebrated today, nor is it identical to the biblical Yom Teruah.


How was the prior Yom Teruah celebrated?

Leviticus 23:25 describes the elements of Yom Teruah. It “shall be a solemn rest to you, a memorial proclaimed with the blowing of horns, a holy convocation. You must do no kind of servile work, and you must bring an offering made by fire to the Lord.” Numbers 29:1–6 supplements this requirement by describing the sacrifices.


Apparently, this day was chosen as a holiday that should be proclaimed to the people by blowing horns because of the number seven. Seven was a significant number. It was even a magical number among the pagans. The ancients saw the number everywhere – such as the body parts, two legs, two arms, two parts of the torso, and the head, and seven heavenly bodies among the stars.


The Jews also considered seven important because it reminded them of the existence of God, who created the world in six days, rested on the seventh, and gave them laws. Among many other uses of seven, they celebrated the Sabbath on the seventh day, Chag Hamatzot and Sukkot for seven days, marked seven weeks by counting them between Chag Hamatzot and Shavuot, celebrated seven years with a Shemitah Year, and seven Shemitahs with the Jubilee year. They celebrated the first day of the seventh month as another reminder of the significance of seven by adding months to its use in days, weeks, years, and Shemitahs.


Thus it is clear that the invention of Rosh Hashanah and all of its practices, including the idea that this is a day when Jews should repent and resolve to improve one’s self and society, was instituted after the period of Ezra the Scribe, after the promulgation of the Torah, and after around 500 BCE. Yet it should be observed as tradition commands. It has much meaning for Jews today.