The history and the law alike agree therefore in regarding the kingship as somewhat of an excrescence upon the national polity; and this law, where alone the king's existence is recognised, confines itself strictly to securing the theocratic character of the constitution. He must be chosen by Yahweh; he must be a born worshipper of Yahweh, not a foreigner; and he must rule in accordance with the law given by Yahweh. Further, the ideal Israelite king must be on his guard against the grossly voluptuous luxury which Oriental sovereigns have never been able to resist, either in ancient or modern times; and also against the lust for war and conquest which was the ruling passion of Assyrian and Egyptian kings. Evidently too the ideal king of Israel was, like Bedouin sheikhs now, expected to be rich, able to maintain his state out of his own revenues. The tribute paid by subject peoples, together with the booty taken in war and the profits of trade, were his only legitimate sources of income beyond his own wealth. Every other exaction was more or less of an oppression. He had no right to make any claims upon the land, for that was held direct of Yahweh. Nor were there any regular taxes, so far as the Old Testament informs us. The only approach to that would appear to be that the presents with which his subjects voluntarily approached the king were sometimes and by some rulers made permanent demands; at least that would seem to be the meaning of the somewhat obscure statement in 1 Sam. xvii. 25 that King Saul would reward the slayer of Goliath by making "his father's house free in Israel." Some kind of regular exaction from which the victorious champion's family should be free must here be referred to; but it would not be safe, in the absence of all other evidence, to suppose that regular taxes in the modern sense are referred to. More probably something of the nature of the "benevolences" which Edward IV. introduced into England as a source of revenue is meant. If a popular and powerful king of Israel was in want of money, he could always secure it by ordering those able to afford handsome presents to appear yearly before him with such gifts as a loyal subject should offer. For the convenience of all parties an indication of how much would be expected might be made, and then he would have what to all intents and purposes would be a tax. Along with this he might also enforce the _corvée_; but such things were always regarded as excesses of despotic power. That Samuel in his _mishpat hammelekh_ (1 Sam. viii. 15) warns the people that the king would demand of them a tithe of their cereal crops and of the fruit of their vineyards and of their sheep, does not contradict this reading of the passage in 1 Sam. xvii. For though chapter viii. belongs to the later portion of 1 Samuel and may therefore represent what the kings had actually claimed, yet it in no way endorses such demands. On the contrary, it indicates that such exactions would bring the people into slavery to the king by the phrase "And ye shall be to him for slaves." All that is mentioned there, consequently, is part of the evil the kingship would bring with it, and cannot in any way be regarded as a legal provision for the maintenance of royalty.
It is not probable, therefore, that in these prescriptions the author of Deuteronomy is repeating a more ancient law. No such law has come down to us. Dillmann supposes the provision that the king should always be an Israelite to be ancient; and indeed at first sight it is difficult to see why such a provision should be introduced for the first time in the last days of the Southern Kingdom, where the kingship had so long been confined, not only to Israelites, but to the Davidic line. But Jer. xxxii. 21--"Their potentate shall be of themselves, and their governor shall proceed from the midst of them"--shows that, whatever the cause might be, there was in the first years of the sixth century a longing for a native king similar to that here expressed. In any case, as the obvious intention here is to make entire submission to Yahweh the condition of any legitimate kingship, it was only consistent to require expressly that the king should be one of Yahweh's people. That motive would be quite sufficient to account for raising what had been the invariable practice into a formulated law; and no other of the prescriptions need have been ancient. On the other hand, the curious phrase "Only he shall not multiply horses to himself, nor cause the people to return to Egypt to the end that he should multiply horses; forasmuch as Yahweh hath said unto you, Ye shall henceforth return no more that way," can hardly belong to the Mosaic time. There was no doubt then much danger that the people should wish to return to Egypt; but that a king should cause them to return for horses, is too much of a subordinate detail to have been portion of a Mosaic prophecy. If, as is most probable, the phrase condemns the sending of Israelites into Egypt to buy horses and chariots, it can have been written only after Solomon's days. Before that time Israel, as an almost exclusively mountain people, regarded horses and chariots with dislike, and usually destroyed them when they fell into their hands. With the extension of their power over the plains and the growth of a lust for conquest, they sought after chariots eagerly. To procure them they entered into alliances with Egypt which the prophets denounced, and which brought to the nation nothing but evil. It was natural, therefore, that the Deuteronomist should specially mention this detail, and should support it by reference to a Divine promise, which does not appear in our Bible, but which probably was found in either the Yahwistic or the Elohistic narrative.