The Feast of Trumpets (also known as the Festival of Trumpets) was a Hebrew feast established in the biblical Book of Leviticus and reaffirmed in the Book of Numbers — both found in the Old Testament Law. The Feast of Trumpets (Heb: Yom Teruah) marks the beginning of the fall holiday season on the Hebrew calendar. In ancient times, before the Law, this day was the first day of the year. Since the return from exile, the civil year for Jews has reverted to this reckoning, lending to the better known name for the day as "Rosh Hashanah" (meaning New Year, literally head of the year).
Corresponding to the official beginning of the fall harvest, the holiday was to be a time for a pilgrimage to Jerusalem to begin as a ten day purification period before the Day of Atonement. The festival derived its name as "of trumpets" because the feast would be officially initiated by the blow of trumpets.
On the first day of the seventh month of the Hebrew calendar (eventually reverted to the first month after the exile in national Israel) was the day set apart for the Feast of Trumpets. On this day no regular labor was to be performed, but a sabbath rest was to happen. A sacred assembly would come to order, commemorated by the blowing of trumpets. Two silver trumpets would both be blown with two blasts to call all of Israel into assembly. The trumpets would be blown by Levites, the "sons of Aaron". While every feast had trumpets blowing as a memorial of God, only the regulations concerning the Feast of Trumpets specifically called for it. In all other cases a general regulation was to be applied that is not found specifically in the prescriptions for the holiday. Since the feast had no assigned name, it eventually became known as the "Feast of Trumpets".
Sacrifices and Offerings
In order to create an aroma pleasing to God a food offering would take place, in addition to the regular prescribed offerings. The offering's animal sacrifices would consist of one young bull, one ram and seven male lambs; all without defect. Alongside this three-tenths of an ephah of olive oil, and one-tenth of an ephah with the bull and lambs respectively. A male goat was to also be included as a sin offering as atonement.
Since trumpet blasting was a designated method of calling Israel into order, throughout Scripture trumpets have not only a literal use, but a symbolic meaning attached. This is especially the case in prophecies, like the Book of Revelation that refer to trumpets being used.