The Book of Mormon people lived the Law of Moses and celebrated the festivals. Described in Leviticus 23, the fall feasts are the Feast of Trumpets (now called Rosh Hashanah), the Day of Atonement (known as Yom Kippur) and the Feast of Tabernacles. Coinciding with the agricultural harvest, these feasts are symbolic of the spiritual harvest of souls.
The Feast of Trumpets begins on the 1st day of the seventh month in the Jewish lunar calendar, (around Sept.-Oct. in our calendar). It begins on a Sabbath, and is celebrated by introspection, repentance, and burnt offerings. The ten days between the Feast of Trumpets and the Day of Atonement are days of repentance.
The Day of Atonement is a day of fasting. The High Priest enters the Holy of Holies and makes an offering to God on behalf of all the people. The offering is symbolic of the sacrifice of the promised Messiah, and His atonement for their sins.
Five days later, the Feast of Tabernacles begins on the Sabbath day. The people commemorate their time in the wilderness by living in makeshift huts. Burnt offerings, and many other offerings, are made every day during this week of celebration.
Moroni, the Book of Mormon prophet, knew the Law of Moses. His September visits to Joseph Smith always coincided with the Feast of Trumpets, the ancient celebration of the harvest. Today, in this great and last dispensation, a statue of Moroni stands on top of all our temples. He blows his trumpet, announcing to the world that the great harvest of souls has begun!