Rabbi Moshe Avigdor Amiel
The clock and the shofar
There is a simple clock that indicates the hours, and there is an alarm clock that apart from the role of any clock, it has one more function: to awaken the sleeping and rouse the napping. The first acts only through the sense of sight, and the second by both the sense of sight and the sense of hearing.
Rosh Hashana is a kind of clock, the alarm clock. Not only does it show the years, and like the clock - the hours, it also awakens, with the hearing sense, the sound of the shofar that calls: " Wake up, you sleepy ones from your sleep and you who slumber, arise."