One of the peculiarities of Rosh Hashana is that it cannot seem to make up its mind as to whether it is a joyous festival or a day of fear and trembling. Most holy days are one or the other. On the one hand, it is a time when we eat apples and honey and other dishes that symbolize the joy and expectation of happiness for the new year. We wish each other a "good and sweet year." On the other hand, we constantly refer to it as Yom Hadin - the Day of Judgment - and in many prayers and poems we describe the terror of facing that judgment. "Who shall live and who shall die, who shall perish by water and who by fire..." is hardly a joyous thought. The basic s tructure of the service indeed resembles those of the three festivals of joy - but the Hallel that symbolizes that is missing. The Sages explained this by saying that one cannot recite the Hallel when standing before the supreme judge of all. How can we explain this combination of contradictory emotions? Perhaps the historical development of the day accounts for its unusual nature. To begin with, Rosh Hashana is not the name of the day in the Torah. Nor is it called the Day of Judgment. Rather it is is referred to simply by its date and as a day of "sounding the horn" (Numbers 29:1) or "making loud blasts" (Leviticus 23:24). Most scholars see this as a reference to the proclamation of God as sovereign of the world, the commemoration of the coronation of God, as it were. As the beginning of the seventh month, it is a glorified Rosh Hodesh. All of this inclines toward the side of celebration and rejoicing. Nor is there any indication that originally there was any connection whatsoever between that day and Yom Kippur, the 10th of the month. The 10th of the month was, from the very beginning, a time of atonement, of cleansing from sin, be it ritual or moral. That is indeed a cause of solemnity. When the connection to Rosh Hashana was made, sometime in the period of the Second Temple, Rosh Hashana took on a new character. Not only did it become the "beginning of the year for the counting of years" (Mishna Rosh Hashana 1:1) but it also was described as the time when all human beings pass before God in review as troops pass in review before their commander (ibid 1:2). The solemnity of Yom Kippur cast its shadow backward so that the Day of Atonement now was preceded by the Day of Judgment, one leading to the other. The natural result of this connection was that judgment was pictured not only as solemn, but even as frightening. How can one stand before God in judgment and not tremble? The ultimate expression of this is found in the piyyut Unetaneh Tokef, which has come to take a most central place in the liturgy. This poem, which resembles remarkably an early Christian prayer known as Dies Irae - Day of Wrath - is largely based on descriptions of the day of the last judgment that are found in apocalyptic writings that were Jewish in origin but were not accepted into our Scripture. The Sages and later writers simply borrowed that terminology and transferred it from the end of days (which is what is described in Dies Irae) to a yearly judgment that each human being undergoes every single year. It is in keeping with the basic Jewish concept of God that nevertheless God's mercy is stressed rather than God's justice, so that "repentance, righteousness and prayer can avert the severe decree." It is the complicated history of Rosh Hashana that helps us understand the fact that the day has more than one face. Yet there may be more to it than that, for the combination of happiness and fear, of rejoicing and trepidation is a wonderful expression of life itself. To see life as all light and joy would be Pollyannaish to say the least. To view it always as fearful and uncertain would make it difficult if not impossible to live. And so in a brilliant stroke we combine the two, tempering joy with apprehension and diluting fear with hope and happiness. Thus in a way the two faces of Rosh Hashana merge into one face that reflects the truth of human life and helps us to confront our fears and live happily despite the sorrows that are unavoidable. The writer is the head of the Rabbinical Court (Beit Din) of the Rabbinical Assembly of Israel.