Rosh Hashanah is referred to in the Torah as "Yom Teruah", which translates to "the Day of the Sounding of the shofar" or "the day of the awakening blast". It is important that everyone hear the sound of the shofar. Teruah means "an awakening blast" and can also be translated as a "shout". The overarching theme of Rosh Hashanah is that of awakening.
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)
Rosh Hashanah is celebrated ten days before the next Jewish festival called Yom Kippur, the Day of Atonement (which will be on October 7 this year). These ten days are used as a time of repentance, reflection, and rededication to God. The Day of Atonement, is the day when the High Priest would enter the Most Holy Place in the Tabernacle, and sprinkle blood on the Arc of the Covenant for the forgiveness of sins for the people of Israel. It is also prophetic of a final day of Atonement, when God will judge the world.
A typical greeting during Rosh Hashanah is "L'Shanah Tovah Tikatevu", which means "May you be inscribed (in the Book of Life) for a good year." The ten days between Rosh Hashanah and Yom Kippur are given for repentance, in order that no one would be left out of the Book of Life. It is a time of grace, remembrance, and renewal.
There are two major points surrounding the celebration of Rosh Hashanah, creation and judgment. It is a celebration of the creation of the world, a remembrance of what God did in the beginning, but it is also a reflection on the future judgment and atonement of creation. So, this is a celebration of both the beginning and the end of creation. It celebrates how God spoke everything into existence, and how God will write the names of the saved into the Book of Life.
"The LORD said to Moses, "Speak to the Israelites and say to them: 'These are my appointed feasts, the appointed feasts of the LORD, which you are to proclaim as sacred assemblies." (Leviticus 23:1-2)
It is important to understand that this is NOT a "Jewish Holiday", it was given as a command from God as a "sacred assembly". There are seven such assemblies that God instructed Moses about. These sacred celebrations include Sabbath (Lev. 23:3), Passover (Lev. 23:5), Unleavened Bread (Lev. 23:6), Firstfruits (Lev. 23:9-14), Feast of Weeks (Lev. 23:15-22), Feast of Trumpets (Lev. 23:24), Day of Atonement (Lev. 23:27), and the Feast of Tabernacles (Lev. 23:34).
Realizing that these festivals, feasts, and Holy days are given as special event markers to remind us of what God has done, but they also serve as prophetic signs of what God will do. We have already seen the Messianic fulfillment of the spring festivals (Passover, Unleavened Bread, and Firstfriuts) with the first coming of Christ.
Jesus was our Passover lamb, offered up as a pure sacrifice, without any leven, for the forgiveness of sins. When Jesus ate the Passover meal with his disciples, he instructed them to do it in remembrance of him (Luke 22:19). Passover, being the celebration of salvation from the bondage and slavery in Egypt, has now become for us the celebration of salvation from the bondage of sin.
Fifty days later, on the celebration of Firstfruits (Pentecost), Jesus sent the Holy Spirit to his followers. Pentecost, originally a celebration of the giving of the Law, has become for us a celebration of the giving of the Holy Spirit.
Likewise, just as the spring festivals celebrate the first advent of Christ, the fall festivals are to be a celebration of the return of Christ. Yom Teruah (the feast of Tabernacles) is a celebration of the return of Christ at the sound of the trumpet (Matt. 24:30-31, 1Cor. 15:52, 1Thess. 4:16, Rev. 11:15). The Shofar (ram's horn) is blown 100 times in the synagogue, and is considered the most common symbol of Yom Teruah (or Rosh Hashanah) . The trumpet sound is also a common symbol connected to the return of the Messiah and the judgment of the world.
So, I want to encourage you to celebrate and look forward to Christ's return on Tom Teruah, the festival of Trumpets, for no one knows the day or the hour of His return, but we can be assured that He will return. Also, use this as a time of reflection, repentance, and renewal, seeking to have your name written in the Book of Life.