Blowing the shofar, a well-known multi-purpose call in biblical times, was used to announce significant events. It was employed to herald the Creation, the Revelation at Mount Sinai, and the exhortations of the prophets. Additionally, it served as a military signal, proclaiming an advance or retreat. Furthermore, it marked calendrical occasions, such as the beginning of a new month. Moreover, it proclaimed the Word of God. One day, it will be heard once again during the return of the Messiah.
The shofar is explicitly commanded in the Torah (Numbers 29:1). It possesses two primary and seemingly contradictory purposes: as a call to war (Numbers 10:1-10) and as a proclamation of freedom (Leviticus 25:9).