"And YAHWEH spake unto Moshe, saying, Speak unto the children of Israel, saying, In the seventh month, in the first day of the month, shall ye have a Sabbath, a memorial of blowing of trumpets, an holy convocation. Ye shall do no servile work therein: but ye shall offer an offering made by fire unto YAHWEH." Wayyiqra (Leviticus) 23:23-25¶
The Feast of Trumpets and New Moon This was held on the first day of the seventh month Tishri our October which began the civil year of the Jews. It corresponded to our new years day and on it, from morning to evening horns and trumpets were blown. After the exile the day was observed by the public reading of the law and general rejoicing. 1.
It is not definitely known when Rosh Hashana, which falls on the first day of the month of Tishri, became the first day of the New Year. The scripture (Wayyiqra (Leviticus) 23:24; Bemidbar (Number) 24:1) merely refers to it as a festival which is to take place on the first day of the seventh month, taking Nisan, in the spring, as the first month, as stated in Shemoth (Exodus) 12:1. Nor is it indicated in the eighth chapter of NehemYah (Nehemiah), where a description of the celebration of the holiday is given, that it marks the beginning of the year.
Without entering into the complicated discussion as to whether the ancient Jewish calendar followed the solar or lunar year, it can be asserted that even in early times Tishri practically began the year. Several references in the Pentateuch itself confirm the notion that the month of Tishri initiated the practical year. Shemoth (Exodus) 24:22 speaks of the Feast of Ingathering, or Sukkoth, as the turn of the year. Debarim (Deuteronomy) 31:10-11 speaks of Sukkoth as taking place at the end of the year. Since Sukkoth falls on the 15th of the month of Tishri, it could not begin the year, for such beginning must take place on the first of a month and not in the middle. Both passages are therefore to be understood as meaning that the holiday occurs in the month which begins the year. In fact, the very commandment that the shophar (ram's horn; trumpet) shall be sound on the first of Tishri points to its special solemnity, for in scriptural times the shophar was sounded on important public occasions. However, be that as it may, an old mishnaic statement hailing from early Soferic times (c.350-330 B.C.E.) speaks of the 1st of Tishri, in a very matter-of-fact manner, as the beginning of the civil year. It is evident that it had acquired that status at least several centuries earlier.
In the Agada (Haggadah), it marks the anniversary of the creation of the first human couple, their sin and their repentance. The same idea is expressed in the Rosh Hanana Musaf prayers, where it is stated, "This day marks the beginning of THY work, a memorial of the first day of creation." The principle ceremony is the blowing of the shophar, which is a call for spiritual awakening. The ram's horn recalls Abraham's willingness to offer Isaac, and YAHWEH's acceptance of a ram in place of a human being. Many and complex penitential ideas are associated with the various notes of the shophar.2.
Shemoth (Exodus) 19:18 And mount Sinai was altogether on a smoke, because YAHWEH descended upon it in fire: and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly. 19 And when the voice of the trumpet sounded long, and waxed louder and louder, Moses spake, and Elohim answered him by a voice. 20 And YAHWEH came down upon mount Sinai, on the top of the mount: and YAHWEH called Moses up to the top of the mount; and Moses went up. 21 And YAHWEH said unto Moses, Go down, charge the people, lest they break through unto YAHWEH to gaze, and many of them perish. 22 And let the priests also, which come near to YAHWEH, sanctify themselves, lest YAHWEH break forth upon them.
Mishnah (Etymology:Hebrew mishnah instruction, oral law Date:1610) the collection of mostly halakic Jewish traditions compiled about A.D. 200 and made the basic part of the Talmud (: the body of Jewish law supplementing the scriptural law and forming especially the legal part of the Talmud; Etymology: Hebrew halakhah, literally, way Date:1856)
Agada (Haggadah) (Etymology:Hebrew haggdhh Date:1856)
1: ancient Jewish lore forming especially the nonlegal part of the Talmud
(Etymology:Late Hebrew talmudh, literally, instruction Date:1532): the authoritative body of Jewish tradition comprising the Mishnah and Gemara
2 : the prayer book containing the seder ritual ( a Jewish home or community service including a ceremonial dinner held on the first or first and second evenings of the Passover in commemoration of the exodus from Egypt)
ALL FEAST BEGIN AT SUNSET THE DAY BEFORE THE FEAST DATE.
1. The Zondervan Pictorial Bible Dictionary cc1963
2. Encyclopedaedia Britannica (Jewish Holidays) 1968