Rashi explains, “When a human being blows a trumpet, the longer he blows it, the more tired he becomes and the weaker the sound grows”.
But the shofar at Mount Sinai was different. Not only did its sound constantly increase in volume, but it has continued to be heard ever since. Its sound will not cease until “the earth is as full of the knowledge of God as the waters cover the sea” (Isa. 11:9).
Rabbi Levi Yitzchak of Berditchev comments, “There are people who hear the sound of the Rosh HaShanah shofar all year long… and there are people who hear the sound of the Mount Sinai shofar all the days of their lives.”
They are two different shofarot. The Rosh HaShanah shofar calls us to repentance, and we should repent every day of the year. The Mount Sinai shofar proclaims God as king over the world, and this thought ought to accompany us every day of our lives.
Otherwise, as the High Holyday prayers suggest, we will be caught up in the constant tussle between the melech evyon, the over-confident human tendency to think one is self-sufficient, and the melech elyon, the Creator King who expects humility of His creatures, and the capacity to listen to the Divine word and live a life of dignity and responsibility.