In Le 23:23-25 the first day (new moon) of the seventh month is set apart as a solemn rest, "a memorial of blowing of trumpets" (the Hebrew leaves "of trumpets" to be understood), signalized further by "a holy convocation," abstinence from work, and the presentation of "an offering made by fire." In Nu 29:1-6 these directions are repeated, with a detailed specification of the nature of the offering. In addition to the usual daily burnt sacrifices and the special offerings for new moons, there are to be offered one bullock, one ram, and seven he-lambs, with proper meal offerings, together with a he-goat for a sin offering.

The significance of the feast lay in the fact that it marked the beginning of the new year according to the older calendar. Originally the "revolution" of the year was reckoned in the fall (Ex 23:16; 34:22), and the change to the spring never thoroughly displaced the older system. In fact the spring New Year never succeeded in becoming a specially recognized feast, and to Jewish ears "New Year's Day" (ro'sh ha-shanah) invariably signifies an autumnal festival. So the Mishna (Ro'sh ha-shanah, i.1): "There are four periods of commencement of years: On the 1st of Nisan is a new year for kings and for festivals; the 1st of Elul is a new year for the tithe of cattle.... The 1st of Tishri is new year's (day) for the ordinary or civil year, for the computation of 7th years, and of the jubilees; also for the planting of trees, and for herbs. On the 1st of Shebat is the new year for trees."

The ritual for the day consequently needs little explanation. All new moons were heralded by trumpeting (Nu 10:10), and so the custom was of course observed on this feast also. There is nothing in the language of either Le 23 or Nu 29 to require a prolongation of the music on this special new moon, but its special distinction was no doubt marked by special trumpeting at all times, and at a later period (see below) elaborate rules were laid down for this feature. The additional sacrifices simply involved an increase of those prescribed for new moons (Nu 28:11-15), without changing their type. Perhaps Ps 81 was especially written for this feast (compare 81:3).

Mentions of a special observance of the 1st of Tishri are found also in Eze 45:20 (reading, as is necessary, "first day of seventh month" here for "seventh day") and Ne 8:1-12. In the former passage, the day is kept by offering a bullock as a sin offering and sprinkling its blood in a way that recalls the ritual of the Day of Atonement. In Nehemiah an assembly of the people was held to hear Ezra read the Law. The day was kept as a festival on which mourning was forbidden (Ne 8:9). Apart from these references there is no mention of the feast elsewhere in the Old Testament, and, indeed, there is some reason to think that at one time the 10th, and not the 1st, of Tishri was regarded as the beginning of the year. For Eze 40:1 specifically calls this day ro'sh hashanah, and Le 25:9 specifies it as the opening of the Jubilee year (contrast the Mishna passage, above). Consequently scholars generally are inclined to assign Le 23:23-25 and Nu 29:1-6 to the latest part of the Pentateuch (Ps). This need not mean that the observance of the 1st (or 10th) of Tishri was late, but only that the final adoption of the day into Israel's official calendar, with a fixed ritual for all Israelites, was delayed. If the original New Year's Day fell on the 10th of Tishri, its displacement ten days earlier was certainly due to the adoption of the 10th for the Day of Atonement. An explanation of the date of the latter feast would be gained by this supposition.

The instrument to be used in the trumpeting is not specified in the Bible, but Jewish tradition decided in favor of the horn and not the metal trumpet, permitting for synagogue use any kind of horn except a cow's, but for temple use only a straight (antelope's) horn and never a crooked (ram's) horn (Ro'-sh ha-shanah, iii. 2-4). According to iv. 1, when the new year began on a Sabbath the horns were blown only in the temple, but after its destruction they were blown in every synagogue. Every Israelite was obliged to come within hearing distance of the sound (iii.7). In the synagogue liturgy of iv.5-9 (which forms the basis of the modern Jewish practice), four sets of "benedictions" were read, and after each of the last three sets the horn blown nine times. Modern Judaism sees in the signals a call to self-examination and repentance, in view of the approaching Day of Atonement.