The answer is: Feast of Trumpets

Lev 23:24

The Feast of Trumpets, known in Hebrew as Yom Teruah, marks the beginning of the Jewish civil year and falls on the first day of the seventh month, Tishrei. It’s a time of solemn assembly and reflection, heralded by the sound of the shofar, a ram's horn that has the ancient power to call the faithful to attention. Interestingly, this unique practice stems from a historical backdrop where such sounds signified not just religious occasions but moments of war, signaling citizens to gather.

This feast kicks off a spiritual journey leading up to Yom Kippur, the Day of Atonement, ten days later. The period, known as the Ten Days of Repentance, is a time for self-examination and reconciliation—perfect themes as the autumn season represents a time of harvest in many cultures, including those in the Bible. The gathering of God's people during this feast reminds us of accompanying calls throughout Scripture, like Genesis 22, where faith and sacrifice play significant roles indicative of divine mystery.

What's fascinating is that the tradition of setting aside a particular day for trumpet sounds and collective reflection has echoed through history, influencing many celebrations, including New Year's in some cultures. The early Christians also reinterpreted these events, adding layers of meaning to reconnecting with contributions from Jewish traditions while framing them within the life of Jesus—the prophetic fulfillment that was keenly awaited during those ancient feasts.