Shofar שופר

The Torah calls the first day of the seventh month "a day of sounding"—and explains nothing more. Tradition chose the ram's horn—for the ram that took Isaac's place on the altar—and three kinds of sound: tekiah, one long note; shevarim, three groans; teruah, nine sobs.

Maimonides wrote that the shofar cries without words what words cannot say: "awake, you sleepers". The shofar was sounded at the anointing of kings and in the jubilee year; it proclaimed war and liberty; from the Temple wall a blast announced the Sabbath. The laws—which horn is fit, which sounds are required—are in tractate Rosh Hashanah.