The Mishnah in Tractate Rosh Hashanah tells us about four days of judgment each year: Pesach, Shavuot, Rosh Hashanah, and Sukkot.
The Gemara explains that each day has a special offering that helps us merit a favorable judgment. On Pesach, the Almighty judges the wheat in the field, so in His mercy He gave us the mitzvah of bringing the Omer offering. On Shavuot, when the Almighty judges the fruit of the trees, we bring bikkurim, the first fruits, as a gift to the priests in the Temple. On Sukkot, the time comes for judgment concerning the winter rains, and so we pour water on the Altar.
And what about Rosh Hashanah, when the Almighty judges people? What offering can we bring to merit a good year?
Rabbi Shlomo Zalman Auerbach answers that, regarding Rosh Hashanah, the Sages drew our attention to the Torah's words “Va'asitem olah”: you shall make an olah offering, instead of the usual word “Vehikravtem”—you shall offer a sacrifice. The commentators explain that, in practice, this means that each person must make themselves into an offering.
But how can a person make themselves into an offering? Rabbi Shlomo Zalman says that willingly accepting the Creator's judgment for the coming year is itself an acknowledgment of the Almighty as one's King. If we merit standing in fear and awe and understanding that our entire lives are being decided during these few moments in the synagogue, and if we believe this with all our hearts, we dedicate ourselves to the King of Kings!