The Lord spake unto Moses. It must have been during the years of wandering, but within those limits it is impossible even to conjecture the probable date. There is no external evidence, and the internal evidence is wholly indecisive.
Neither can it be reasonably maintained that these regulations were designed to revive the hope and sustain the faith of the rising generation. Incidentally they may have had some effect in that way, but it is evident that the primary object of their promulgation was simply to supply certain defects and omissions in the Levitical legislation.
Why that legislation should have had the fragmentary and unfinished character which it so evidently bears, requiring to be supplemented, here by an isolated commandment, and there by oral tradition, is an interesting and difficult question; but there can be no doubt as to the fact, and it is superfluous to look any further for the reason of the enactments here following.