The post-exilic reforms of the jewish community were inspired by the so called King Josiah‘s Reform (cfr. 2 Kings 22-23; 2 Chr 34). The first reform was the centralization of worship in Jerusalem. Deuteronomy 12 – the chapter which opens the so-called “Deuteronomic Code” (Deut 12-26) – speaks about that reform.
In fact, the Temple of Jerusalem becomes the central institution of the whole post-exilic period. It called “Second Temple” which will be destroyed by Romans in 70 A.D. However, Josiah wasn’t able to centralize the cult in Jerusalem, because at his times there were many others shrines dedicated to other gods. The centralization of israelite cult at Jerusalem is typical of the times of prophets Haggai and Zechariah, when the Temple of Jerusalem was actually rebuilt (520-515 BC).
The second element of the structural reform is the new ritual of Passover. The account of the King Josiah’s reform culminates with the celebration of Passover (cfr. 2 Kings 23:22). The scholars think that the whole story of the “Reform of Josiah” should be dated to the post-exilic period. The new ritual blends together two very ancient festivals in Israel. The first one was the farmers’ festival of the “Unleavened Bread” (in Hebr. mazzot) to be celebrated in the month of the ears. The second was the sacrifice of the lamb, by which the shepherds ensured the protection of the entire flock. This two rituals were included in the Deuteronomic reform (Dt 16). Before that time there is no evidence of Passover’s celebration. In fact, the celebration of Passover is not attested in any of the pre-exilic prophetic texts; this would mean that the Passover ritual is to be dated to post-exilic times and it is one of the reforms introduced in the period of reconstruction of the Temple.
The third element of the great Deuteronomic reform is the the weekly celebration of shabbat. Before the sixth century BC, it was celebrated once a month. Probably before the exile the shabbat was the festival of “full moon”, called shapattum in the Mesopotamian calendar, as opposed to the “new moon” feast. This appears clearly in the prophet Amos (8:5; Hos 2:13 and Is 1:13 – VIII cent. BC).
The book of the prophet Ezekiel – dated to the exilic period – speaks about shabbatot (plural of shabbat), suggesting a stage where Shabbat was celebrated both on a weekly basis and on a monthly basis (Ez 20:23; 16:21.24; 22,8; 23,38). More likely, Ezekiel testifies a phase of transition from the shabbat celebration once a month to a celebration once a week.
Surely the creation of the weekly celebration of the Shabbat is of central importance in the postexilic Jewish community, as a special and central day of the week and totally consecrated to God. The most complete statement regarding the week ending with the Shabbat celebration is Dt 5:12-15. Probably this text was the chronological framework of the creation of the world (see Dt 5:13). In this sense, the human week is a reflection of God’s creative work and, conversely, the creative work of God in seven days is the model of the human week.
The last element, described in Deuteronomy 17-18, concerns the governance structure of the post-Jewish community. The Deuteronomic model included the presence of a king in the government flanked by a priest and a prophet, as part of the observance of Torah. This ideal society was probably achieved at the time when Zerubbabel (Persian governor who rebuilt the Temple in Jerusalem) and the prophet-priest Zechariah lived. This ideal society doesn’t last very long, because Zerubbabel and Zechariah were displaced by the high priest Joshua. It was a real coup d’etat that brought he secular government of Judea to an end. This coup was theologically justified by the prophetic writings of Haggai and Zechariah.
In conclusion, the Deuteronomic reform movement gave a new configuration to Ancient Israel (i.e. the pre-exilic Israel). To formalize the reform, the Deuteronomy’s author makes Moses speak in the first person. Moreover he anchors all the reform’s innovations to the myth of the reform of Josiah the king that renewed the ancient Mosaic law (i.e. the Torah).