But this is not all. The Pentateuch itself is not a unity. It consists of different strata of legislation which, while irreconcilable in details, are held to exhibit a continuous progress towards a clearer definition of the duties that devolve on different classes in the community, and a fuller exposition of the principles that underlay the system from the beginning. The analysis of the Mosaic writings into different legislative codes has resulted in a scheme which in its main outlines is now accepted by critics of all shades of opinion. The three great codes which we have to distinguish are: (1) the so‐called Book of the Covenant (Exod. xx. 24‐xxiii., with which may be classed the closely allied code of Exod. xxxiv. 10‐28); (2) the Book of Deuteronomy; and (3) the Priestly Code (found in Exod. xxv.‐xxxi., xxxv.‐xl., the whole book of Leviticus, and nearly the whole of the book of Numbers).(210) Now of course the mere separation of these different documents tells us nothing, or not much, as to their relative priority or antiquity. But we possess at least a certain amount of historical and independent evidence as to the times when some of them became operative in the actual life of the nation. We know, for example, that the Book of Deuteronomy attained the force of statute law under the most solemn circumstances by a national covenant in the eighteenth year of Josiah. The distinctive feature of that book is its impressive enforcement of the principle that there is but one sanctuary at which Jehovah can be legitimately worshipped. When we compare the list of reforms carried out by Josiah, as given in the twenty‐third chapter of 2 Kings, with the provisions of Deuteronomy, we see that it must have been that book and it alone that had been found in the Temple and that governed the reforming policy of the king. Before that time the law of the one sanctuary, if it was known at all, was certainly more honoured in the breach than the observance. Sacrifices were freely offered at local altars throughout the country, not merely by the ignorant common people and idolatrous kings, but by men who were the inspired religious leaders and teachers of the nation. Not only so, but this practice is sanctioned by the Book of the Covenant, which permits the erection of an altar in every place where Jehovah causes His name to be remembered, and only lays down injunctions as to the kind of altar that might be used (Exod. xx. 24‐26). The evidence is thus very strong that the Book of Deuteronomy, at whatever time it may have been written, had not the force of public law until the year 621 B.C., and that down to that time the accepted and authoritative expression of the divine will for Israel was the law embraced in the Book of the Covenant.