We are continuing in Tractate Sanhedrin, chapter 2, Mishnah 4, which also deals with the rights and obligations of the king: leading the nation out to war, the right of passage through others' property, the division of the spoils of war, and the restrictions the Torah placed on the multiplication of wives, horses, and money - and finally, the mitzvah of the special Torah scroll for the king.
"Umotzi lemilchemes hareshus al pi beis din shel shivim ve'echad" - he leads the people out to a discretionary war by the directive of a court of seventy-one:
When the king wishes to lead the nation out to a discretionary war, he must receive the approval of the Sanhedrin of seventy-one. An obligatory war, however, does not require this approval: uprooting the seven Canaanite nations or wiping out Amalek were already explicitly permitted in the Torah, and the king is permitted to go out to them on his own accord.
The same applies, according to the Rema, when Jewish lives are in danger and enemies come to kill them - it is a mitzvah to defend them and attack the enemy, and this does not require the approval of the Sanhedrin. A discretionary war, on the other hand, is a war that the king initiates by choice: expanding borders based on economic, political, or strategic considerations, and for this, the approval of the Sanhedrin is required.
It is worth noting that the approval of the Sanhedrin is a necessary but not sufficient condition. The sequence of events is:
The approval of the king's advisor and strategist.
The approval of the Sanhedrin.
The approval of the Urim VeTumim.
And only then - the actual execution of the war together with the army commander.
"Uforetz la'asos lo derech ve'ein memachin beyado" - he breaches to make a path for himself, and no one may protest against him:
These are, in fact, the laws of expropriating land. When the king passes with his entourage from place to place and private property blocks his path, he is permitted to breach whatever stands before him - trampling gardens, breaking walls and fences - to reach his destination, and no one has the right to protest against him. Furthermore: "Derech hamelech ein lah shiur" - the king's path has no measure - there is no limit to the width of the path. If the king's entourage is wide, and he needs a wide strip of land to pass through, he has the right to do so, and there is no limit on the amount he needs for passage.
A tangible example of this can be seen at the Jaffa Gate in Jerusalem: the large breach in the wall, through which cars travel next to the gate itself, was made upon the arrival of Kaiser Wilhelm for a visit to Jerusalem. Since he claimed that his entourage was large and he could not enter the city without it, and the gate was too narrow - they breached the wall to allow his entry.
Is the king permitted to keep the land he breached when passing through it? Rashi's wording implies that the land remains his, whereas the Rambam holds that he cannot do so, and he only has a temporary right of passage. In any case, from the story of Ahab - who was certainly not a righteous man - it emerges that he desired Naboth's vineyard and lacked the power to take it, and indeed he did not take it until Jezebel intervened; this implies like the view of the Rambam.
"Vechol ha'am bozez venosen lefanav vehu nosel chelek barosh" - and all the people plunder and place the spoils before him, and he takes his portion first:
When those who go out to war are successful and return with spoils, the spoils are divided between the king and the people: half to the king and half to the people. All the spoils are placed before the king, and he first selects the parts he desires - but strictly within the limits of his half. The second half is divided among the army, not only among those who go out to battle but also among those who guard the camp, as both share equally in this division.
"Lo yarbeh lo nashim velo yasur levavo" - he shall not multiply wives to himself, and his heart shall not turn away:
The Mishnah quotes the wording of the verse that forbids a king from multiplying wives, lest his heart turn away from Hashem, and sets the limit: "Ella shemoneh esreh" - only eighteen. This is the opinion of the Tanna Kamma. The Rambam and the Raavad disagree as to whether concubines are also to be included in this tally; according to the Rambam - yes.
The source for the number eighteen is an exposition based on King David, who had six wives at that time, and to whom it was said: "And if that were too little, then I would add to you such and such." Two times "such" means another six and another six, making three times six, which is eighteen.
The Tannaim disagree on this matter:
Tanna Kamma: Eighteen wives is the limit, and no more.
Rabbi Yehudah: "Marbeh hu lo, uvilvad shelo yehu mesiros et libo" - he may multiply for himself, provided that they do not turn away his heart. The king may marry more than eighteen, as the concern in the verse is solely about turning his heart. According to this approach, the restriction must be understood as applying to wives who turn the heart away, although it is difficult to determine the exact parameters that define a woman as one of them.
Rabbi Shimon: "Afilu achas umesirah et libo - hareh zeh lo yisaenah" - even one who turns his heart away, he may not marry her. Even a single wife who turns the king's heart away from Hashem is completely forbidden to him. What, then, does the verse "he shall not multiply wives to himself" come to teach? "Afilu keAvigayil" - even like Avigayil. Even if we are speaking of righteous and holy women like Avigayil, eighteen is the upper limit and no more. Thus: wives who turn the heart away - none at all, and worthy wives - up to eighteen.
"Lo yarbeh lo susim ella kedei merkavto" - he shall not multiply horses to himself, but only enough for his chariot:
The verse explicitly forbids multiplying horses. In ancient times, the finest horses came from Egypt, and they were a symbol of status and prestige - much like how people collect luxury cars today. The idea is that he is permitted a vehicle, but he may not accumulate luxuries to display his wealth, as he must be focused on the nation and its needs, rather than on amassing property and self-aggrandizement.
Therefore, the king - who personally funds an army, including a cavalry corps - is permitted to amass the horses required for his cavalry. This does not mean a one-to-one ratio, since it is understood that reserve horses are also needed, because horses get injured, become tired, and sprain legs. The rule is that he may collect horses for military purposes, but not for his personal wealth and to glorify his name.
"Vechesef vezahav lo yarbeh lo meod ella kedei litten apsanya" - and he shall not greatly multiply silver and gold to himself, but only enough to give soldiers' pay:
The same principle applies to money: the king is forbidden to accumulate excessive wealth. He must fund the wages of the standing army from his treasury, and for this he needs sufficient money, but he may not accumulate capital for the sake of wealth, fame, and power. Again, he must focus not on his material well-being and personal advancement, but on the well-being of the people, and therefore the accumulation of money beyond what is necessary is not allowed.
"Vechoseiv lo sefer Torah lishmo" - and he writes a Sefer Torah for himself:
The king writes a Sefer Torah by virtue of being a king. As is known, there is already a mitzvah for every Jew to write a Sefer Torah. Many rely on the opinion of the Rosh, who maintains that the primary point is access to Torah for the purpose of study, and therefore one who keeps a Torah library in his home, as well as a Sefer Torah - has fulfilled his obligation. However, the simple meaning is that every Jew must invest in a Sefer Torah and write it with his own hands, and there are those who fulfill this in other ways, such as by writing a part of a Sefer Torah or a letter in a Sefer Torah.
Nevertheless, the king has an additional obligation: a special Sefer Torah that he writes for himself, a sort of small Sefer Torah that he carries with him everywhere. Even when he goes out to war - and this is the last thing a person would want to carry with him on the battlefield - he is obligated to take it out with him: "Yotzei lamilchamah motziah imo, nichnas - machnisah imo" - when he goes out to war, he takes it out with him; when he comes in, he brings it in with him.
And so too in all his situations: "Yoshev badin - hu imo" - when he sits in judgment, again referring to a king from the House of David, the Sefer Torah is with him. "Meisev - hi kenegdo" - even during his time of rest and his meal, the Sefer Torah is placed opposite him. The king carries the Torah with him to remind himself that he is subordinate to the Almighty: although he is a king, he is merely a servant of the Almighty and of the people, and the symbol of this is the Torah, to which he submits himself. "Shene'emar: vehaitah imo vekara bo kol yemei chayav" - as it is stated: "And it shall be with him, and he shall read from it all the days of his life" - he must submit himself to the Almighty and to His Torah, and be aware of this at all times.