Rosh Hashanah is the (Rabbinic) Jewish New Year, but is Biblically known as Yom Teruah (literally the "Day of [loud] Noise"). It falls on the first day of the seventh month, generally considered by Rabbis as the beginning of creation, and the Mishnah speaks of it as a day of judgement. In the Bible it is known as the Blowing of Trumpets and has the following meanings:

• Gathering and assembling of people
• Commencing a journey
• Call to arms
• Proclamation of joy
• Memorial or reminder of something present or just at hand

Maimonides (a medieval Jewish scholar) said it was to rouse men to repentance
The trumpet sound is connected to the voice of God (Ex.19:19; Rev.1:10) where the Trumpets were saying: "Come my people, gather to me, rejoice."
It is God saying "Behold" to his people: "Behold the bridegroom comes, the day of joy is at hand."

The Lord said to Moses,
"Say to the Israelites: 'On the first day of the seventh month you are to have a day of rest, a sacred assembly commemorated with trumpet blasts. Do no regular work, but present an offering made to the Lord by fire.'"

~ Leviticus 23: 23-25 ~

The Feast of Trumpets (Rosh Hashanah) is now the Jewish New Year, and begins the high Holy Days in the seventh month (corresponding to September or October). It is a celebration of the spiritual birthday of the world or creation, and is celebrated with blowing of the trumpets (Lev. 23:23-25).

Overview:

• Jewish New Year = September / October
• Begins the "High Holidays"
• Celebrates the spiritual birth of the world and creation
• According to Jewish Tradition, many key milestones in God's plan occurred on Rosh Hashanah
• According to Jewish Tradition all the following 'key moments' in Biblical history happened on first day of the seventh month:
• Adam and Eve were created
• The Flood waters dried up
• Enoch was taken by God (Gen. 5:24)
• Sarah, Rachel, and Samuel (1 Sam. 1) conceived
• Joseph freed from prison by Pharaoh
• The forced labour of Hebrews in Egypt ended
• Job contracted leprosy
• Start of sacrifices on the altar built by Ezra (Ezra 3:1)
• The Shofar Ceremony in the Temple
• The ceremony of the blowing of the shofar was a magnificent sight.
• The priest chosen to blow the shofar was trained from childhood. On the first day of this feast, the priest blowing the shofar stood outside the Temple with two trumpeters.

The shofar represents, among other things, a call to awaken the conscience.

There are four different sounds associated with the Feast of Trumpet's service. These sounds are explained as follows:

1) Tekiah – A pure unbroken sound that calls man to search his heart, abandon his evil ways, and seek forgiveness through repentance.

2) Shevarim – A broken, staccato, trembling sound. It typifies the sorrow that comes to man when he realizes his wrong and desires to change his ways.

3) Teruah – A wave-like sound of alarm calling upon man to stand by the banner of God.

4) Tekiah Gedolah – The prolonged, unbroken sound typifying a final invitation to sincere repentance and atonement.

Trumpets were always blown at a new moon; hence this was the 7th trumpet. At this particular feast the trumpets were heard from morning to evening, whereas on other occasions they blew once or twice. The Feast of Trumpets may thus be viewed as foreshadowing the day when God calls the attention of the Church and Israel, as well as of the nations, to the closing events of this age.

The trumpet has been sounding and Israel has been regathered as a nation into their own land. Yeshua said to look at the fig tree..." (Matthew 24:32-33). The sign of the nearness of Messiah's return is the return of Israel to their own land.