The sages of the midrash added another layer to this halacha when they pointed to its unique source. According to them, this halacha is unlike most halachot written in the Torah which God had given to Moshe. This halacha did not come from the ?top down?. The midrash says the following:
Whatever Moshe decreed, the Blessed Be He agreed with him? The Blessed Be He told him to fight Sichon, as it says: ?Behold, I have delivered into your hand Sichon the Amorite, king of Cheshbon, and his land: Begin to possess it, and provoke him to war? (Devarim 2, 24), but Moshe did not do so, but (according to Moshe?s retelling of the war): ??Then I sent messengers from the Wilderness of Kedemoth to King Sichon of Cheshbon with an offer of peace?. Said God to Moshe: I told you to fight him and you offered peace. Now I will fulfill your decree. Every war they go to will start with a peace offering, as it says: ?When you approach a city to wage war against it, you shall propose peace to it?.
(Midrash Devarim Rabbah 5, 13)
This halacha that one must call for peace before waging war, according to the sages of the midrash, was not told to Moshe by God, but the other way around. Moshe was the one who initiated this halacha and God agreed to it and commanded it for eternity. Why, actually, didn?t God instruct Moshe to first offer peace as a last-ditch effort before waging war?
It seems the reason for this is that calling for peace is not something that can be done fully when it is a commandment. It is a step that must be taken by a person?s conscience. When God instructed Moshe to wage war, he expected that Moshe would understand that war is a step taken when there are no other options, and that he would first use every diplomatic means to avoid it. Indeed, Moshe understood this and acted according to his conscience. Only then, when Moshe set the moral norm on his own, did God agree with him and make this the required norm forever.
Many thinkers of the Middle Ages and modern times saw the Jewish nation as a rare phenomenon; a nation that gave up on the idea of a state and preferred to live in exile in order not to be tainted by the moral depravity that comes with national-territorial aspirations.
This pacifist concept is not the entire truth. Though the Jewish nation did, for many generations, prefer to avoid manifest nationalistic aspirations, every single generation remembered the hope that comes with the phrase ?Next year in Jerusalem?. The Jewish nation yearned to return to its land, but hoped and strived for a return that would be accompanied by a ?call for peace? and not war. The Jewish nation is not one that lives by its sword. The prophecy of Isaiah about the days when humanity will make the sword superfluous is a vision that has inspired the Jewish nation for thousands of years.
The Jewish nation never preferred living in exile. It strived to return to its land and live in it peacefully. The only justification for bearing arms, in the eyes of Judaism, is for self-defense. The incessant striving for peace typifies the Jewish nation even in today?s world.
Moshe understood the value in calling for peace and acted accordingly. His brother, Aharon, ?loved peace and pursued peace?. These are the role models of the Jewish people ? in exile and when it has returned to its land.