From the time occupied by Ezra in reading his law it is inferred that it could hardly have been our first five books of the Bible; and since to carry out the laws contained in them would involve endless discussion because of their contradictory character (compare for example the directions for keeping the feast of Tabernacles in Deut. xvi. 13, 15, which commands seven days, with Lev. xxiii. 39, which adds an eighth day for a solemn assembly; compare also the account in 1 Kings viii. 66, with 2 Chron. vii. 8, 10), it is thought that this law of Ezra must have been much smaller than the Pentateuch, and much more homogeneous. The Pentateuch not only contains more than "laws," but even the legal sections bear the marks of such widely different aims and conditions that we are compelled to assume a gradual collection, with continual redaction and codification, in order to account for the various phenomena. The earliest strata may go back to a great antiquity, and the customs themselves must often be primitive Semitic survivals, but the critical contention is that, as a whole, the "Law of Moses" owes its present form to an age later than the Exile, and somewhat later than Ezra himself; for Ezra's code has itself been revised (compare Neh. x. 32, where a third of a shekel is appointed, with Exod. xxx. 13, where it has increased to half a shekel), before it was amalgamated with the Pentateuch in its existing form.
The critical basis for this theory of the gradual formation of the law is found first in the fact that the legislation of the Pentateuch is not homogeneous: it is so contradictory that to carry out the law as it stands would be found impossible. It is claimed that the presence of the various strata can be detected by the numerous repetitions (_e.g._, the commandments exist in three recensions: Exod. xx. 1-17; xxxiv. 17-28; Deut. v. 6-21); by the use of different names for God, by the difference in language and style, and by the change in theological conceptions; and moreover, that these different strata can be roughly assigned to various ages, which can be actually confirmed by the record of their observance in the historical books (compare the provisions made for the Ark in Exod. xxv.-xl.; Num. iii.-iv., with its actual treatment in 1 Sam.).