Judaism in Graeco-Roman antiquity is better known than any other ancient religion apart from Christianity, primarily because of the survival to modern times of traditions about ancient Judaism through rabbinic and Christian literature. However, this same factor creates its own problems of bias in the selection and interpretation of evidence.
The main sources of knowledge about Judaism are the Old and New Testaments and other religious texts preserved in Greek within the Christian Church: the apocrypha and pseudepigrapha, and the writings of Philo of Alexandria and Josephus. The works composed in Hebrew and Aramaic produced by the rabbis after ad70 stress rather different aspects. A fresh light has been shone on Judaism by the chance discovery of Jewish papyri in Elephantine and especially by the Dead Sea Scrolls, which revealed the incompleteness of the later Jewish and Christian traditions even about the 1st cent. ad, the period for which most evidence survives. Pagan Greek and Latin writers emphasized the aspects of Judaism most surprising to outsiders but many of their comments were ignorant and prejudiced.
Many of the basic elements of Jewish worship were shared with other religions of classical antiquity. The prime form of worship was by sacrifices and other offerings in the Jerusalem Temple. In this respect the Jewish cult differed from most in the Greek and Roman world only in the exceptional scrupulousness of its observance; in the assumption of most Jews that sacrifices were only valid if performed in Jerusalem, even though this meant that the sacrificial cult was for many only known from a distance; in the role of the priestly caste, who inherited the prerogative to serve in the sanctuary under the authority of an autocratic high priest who at certain periods also operated as political leader of the nation; and in their strong sense of the special sanctity of the land of Israel and the city of Jerusalem and its shrine.
Of the special elements of Judaism noted in antiquity, most striking to pagans was the exclusive monotheism of Jews: most Jews worshipped only their own deity and either asserted that other gods did not exist or chose to ignore them. Equally strange was the lack of any cult image and the insistence of most Jews by the Hellenistic period that Jewish sacrificial worship was only permitted in the Jerusalem Temple, despite the existence of Jewish temples at Elephantine in Egypt in the 5th cent. bc and at Leontopolis in the Nile delta from the mid-2nd cent. bc to ad72, and the Samaritan temple on Mt. Gerizim, which was destroyed only in the 120s bc.
Jews were in general believed by outsiders to be specially devoted to their religion, a trait interpreted sometimes negatively as superstition, sometimes positively as philosophy. The foundation of this devotion lay in the Torah, the law governing all aspects of Jewish life which Jews considered had been handed down to them through Moses on Mt. Sinai as part of the covenant between God and Israel. The Torah is enshrined in the Hebrew Bible, and pre-eminently in the Pentateuch (the first five books). Jews treated the scrolls on which the Torah was recorded with exceptional reverence; if written in the correct fashion, such scrolls were holy objects in themselves. The covenant, marked by circumcision for males, involved the observance of moral and ethical laws as well as taboos about food and sacred time (especially, the sabbath).
The main elements of Judaism as here presented were already in place by the 3rd and 2nd cents. bc, when the final books of the Hebrew Bible were composed, but the Jewish religion was to undergo much change over the following centuries. One new development was the gradual emergence of the notion of a canon of scripture treated as more authoritative than other writings.
Agreement about the authority of particular books did not lead to uniformity, or even the notion of orthodoxy. The Hebrew Bible left many opportunities for diversity of interpretation. The extent of variety, at least up to ad70, is clear from the Dead Sea Scrolls. Disagreements may have been fuelled in part by diverse reactions to the surrounding Hellenistic culture. The continuation of variety after c.ad100, after which Christians ceased to preserve Jewish texts and Judaism is known almost only through the rabbinic tradition, is uncertain.
From the 2nd cent. bc self-aware philosophies began to proclaim themselves within Judaism: Pharisees, Sadducees, and Essenes, and perhaps others. These groups differed on correct practice in the Jerusalem cult as well as on quite fundamental issues of theology, such as the role of fate and the existence of an after-life. However, apart perhaps from the Dead Sea sectarians, who saw themselves as the True Israel, all these Jews believed that they belonged within a united religion: Josephus, who described the three main Jewish philosophies in detail (Bellum Judaicum 2. 119–66; Antiquitates Judaicae 18. 11–22), elsewhere boasted that Jews are remarkable for their unanimity on religious issues (Contra Apionem 2. 181). The earliest followers of Jesus are best considered in the context of such variety within Judaism.
In the Hellenistic and early Roman periods some aspects of the biblical tradition were particularly emphasized by Jews. Ritual purity as a metaphor for holiness was stressed by Jews of all persuasions: mikvaoth (ritual baths) have been excavated in many Jewish sites in the land of Israel, both Pharisees and Essenes elaborated complex elucidations of the biblical purity rules, and restrictions on the use of gentile foodstuffs became more widespread.
Some Jews indulged in speculation about the end of days, which was variously envisaged as a victory of Israel over the nations under God's suzerainty or the total cessation of mundane life. In some texts a leading role was accorded to a messianic figure, but ideas about the personality and function of a messiah or messiahs varied greatly, and the extent to which messianic expectations dominated Judaism in any period is debated. Much of the extant eschatological literature is composed in the form of apocalyptic, in which a vision is said to have been vouchsafed to a holy seer. All the apocalyptic texts from the post-biblical period are either anonymous or pseudepigraphic, reflecting a general belief that the reliability of prophetic inspiration had declined since biblical times.
Religious ideas of all kinds within Judaism were generated or confirmed by study and midrash (a type of exegesis) of the biblical books. According to Josephus in his defence and summary of Judaism in Contra Apionem 2. 181–220, Jews were uniquely concerned to learn their own law. The primary locus of teaching was the synagogue, where the Pentateuch was read and explained at least once a week, on sabbaths. Special buildings for such teaching, and probably for public prayer, are first attested in Egypt in the 3rd cent. bc. In the late Roman period some synagogue buildings were designed with monumental architecture similar to pagan temples and were treated as sacred places.
The increased ascription of sanctity to synagogues was in part a reaction to the destruction of the Jerusalem Temple by Roman forces under Titus in ad70. The destruction, at the end of the great Jewish revolt of ad66–70, was eventually to have important consequences for the development of Judaism, although new theologies were slow to emerge: Josephus in the 90s ad still assumed that God is best worshipped by sacrifices in Jerusalem, and about a third of the Mishnah (collection of legal opinions), redacted c.ad200, is concerned with the Temple cult.
In the diaspora the Temple had in any case always dominated more as an idea than as an element in religious practice, since only occasional pilgrimage was ever possible. The synagogues at Dura Europus (Mesopotamia) and Sardis (W. Asia Minor) may reveal Judaisms based on synagogue liturgy. An honorific inscription probably of the 3rd cent. ad from Aphrodisias reveals that, in that Jewish community at least, gentile God-fearers may have participated in Jewish religious institutions.
The Judaism of the rabbis differed from other forms of Judaism mainly in its emphasis on learning as a form of worship. Rabbinic academies, first in Yavneh (Jamnia) on the coast of Judaea immediately after ad70, but from the mid-2nd cent. mainly in Galilee and (from the 3rd cent.) in Babylonia, specialized in the elucidation of Jewish law, producing a huge literature by the end of antiquity. Their most important products were the Mishnah, composed in Hebrew c.ad200, and the two Talmuds, redacted (mainly in Aramaic) in Palestine in c.ad400 and in Babylonia in c.ad500; but they also produced a large corpus of midrashic texts commenting on the Bible, and they or others in late antiquity composed the Hekhalot texts, which attest to a continued mystical tradition. .
