|Rosh Hashanah - New Year|
Rosh Hashanah is the first and second days of the first Jewish month of Tishrei. It marks the beginning of the Jewish new year. The celebration of this holiday is marked with solemnity, as it is the day on which the whole world is judged for the coming year. Rosh Hashanah is the birthday of the world, as it was on this day that G-d created Man on the 6th day of creation. Every year, on this day, we proclaim G-d as our one and true King.
We blow the shofar since Rosh Hashanah is the anniversary of the creation of the world, it follows that it is also the anniversary of God being sovereign over the world. Rosh Hashanah is a coronation of sorts, and thus we trumpet the shofar just like at a coronation ceremony.