Rosh Ha-shana is the day on which God creates the new year and grants new life to all His creations. It is a mysterious day, rooted in the transcendent, beyond time and place, and therefore everything about it is hidden and can only be glimpsed little by little. This is why one of its names is keseh, deriving from kisui, “cover.” It is the only holiday that coincides with the beginning of the month, when the obscured moon just begins to reappear (Rosh Ha-shana 8a). The practical manifestation of this hiddenness is that there is some uncertainty about when exactly Rosh Ha-shana is supposed to be. To alleviate this uncertainty, it was celebrated for two days. (See sections 7 and 8 below.)
Like other holidays, there is a mitzva to refrain from melakha on Rosh Ha-shana and to sanctify it through food, drink, and clean clothes. Its unique feature is the mitzva to turn it into a day of remembrance (zikaron) and blasts (teru’a). As we read:
The Lord spoke to Moshe, saying: “Speak to the people of Israel thus: ‘In the seventh month, on the first day of the month, you shall observe complete rest, a sacred occasion commemorated (zikhron) with loud blasts (teru’a). You shall not work at your occupations; and you shall bring an offering by fire to the Lord.’” (Vayikra 23:23-25)
Similarly, we read, “In the seventh month, on the first day of the month, you shall observe a sacred occasion: you shall not work at your occupations. You shall observe it as a day of blasts (yom teru’a)” (Bamidbar 29:1).
In the Amida and kiddush, Rosh Ha-shana is called the “Day of Remembrance” (Yom Ha-zikaron), because on this day God remembers His creations and renews their life for the upcoming year. The term “zikaron” (remembrance) in reference to God means that He comes to someone’s aid and grants them life. So that His kindness is not turned into wickedness by wicked people who would use it for evil, God ordained that blessing would be granted based on one’s deeds throughout the year. If one chooses good, he merits a shefa of goodness and blessing, whereas if he chooses evil (God forbid), the shefa of goodness is minimized, and the person consequently suffers much grief and pain. We see, therefore, that Rosh Ha-shana is a day of remembrance and judgment; God sits on His throne of judgment and appraises His world, judging each person individually and each nation collectively.
The primary judgment of the world hinges on the Jewish people and Eretz Yisrael, as the Jews are God’s people, the heart of the world, upon whom the repair of the world depends. Accordingly, the reward and punishment of the Jews is greater than that of other nations. God therefore judges the Jews first, and the judgment of mankind and the world in general is an outgrowth of this judgment (Rosh Ha-shana 8a-b; Ta’anit 10a). When we blow the shofar, recollections of us ascend to Him positively.
On the day that God remembers His creations, we, too, must awaken ourselves to remember what is most important and fundamental to us – faith in God, the Creator of the World – and, accordingly, to accept His divine yoke upon ourselves. Of course, it is always a mitzva to remember the foundations of faith. But on the day that God designated to recall His creations and judge their every action, for better or worse, we, too, must correspondingly contemplate His kingship, undertake piercing introspection, and resolve to better ourselves. This is the meaning of the commandment to make Rosh Ha-shana a “zikhron teru’a”: By remembering our faith and accepting the yoke of heaven, we tremble with the dread of judgment and the immensity of the responsibility we bear. And this is precisely how we are recalled before God in a positive light, mitigating the severity of judgment and increasing blessing in the world.