Why does the Torah ascribe the message here to Moshe, and in Bamidbar 21:21, to Yisrael?
Rashi: Refer to Bamidbar 21:21:1:1 and note.
Rosh (citing a Midrash): Because Moshe sent a message of Shalom, and Yisrael sent a message of war. R. Levi (or Reish Lakish) explains that, there was no disagreement here, since in the same letter they wrote Shalom at the top, and war at the bottom, as if to say that if Sichon does not accept the peace-terms, they will attack him). 1
Rosh (Ibid.): As the Pasuk writes in Tehilim 120:7 "Ani Shalom ... Heimah la'Milchamah".
What prompted Moshe to send a message of peace to Sichon? What is "Midbar Kedeimos" referring to?
Rashi #1: "Midbar Kedeimos" hints at the Torah, which preceded the world and which was given in the desert. Moshe took his cue from Matan Torah. When Hakadosh-Baruch-Hu came down to Har Sinai to give the Torah to Yisrael, He first offered it to Eisav and Yishmael - even though He knew that they would not accept it. Hence, Moshe sent a message of peace even though Hashem did not command him to. 1
Rashi #2: "Midbar Kedeimos" hints at Hashem, who preceded the world. Moshe took his cue from Hashem, who could well have sent a flash of lightning to destroy the Egyptians, but who sent Moshe from the desert to calmly warn Paroh to send His people out. Hence, he sent a message of peace even though Hashem did not command him to
Da'as Zekenim, Hadar Zekenim and Rosh: "Midbar Kedeimos" is a location that was a desert before Hashem brought water from the rock, but now it was a source of water.
Avodah Zarah, 37b: "Midbar Kedeimos" is another name for Har Sinai and is so-called because Hashem gave the Torah - which preceded the world 2 - on it.
Oznayim la'Torah: "Kedeimos" is a town on the western border of the desert - after which the desert is named - that was given to the tribe of Re'uven. The Torah points out that Moshe sent a message of peace whilst Yisrael were stationed in the desert of Keddeimos, before Hashem commanded him to go and inherit the land and fight Sichon - and Moshe thought that he only needed to ask Sichon for permission to pass through his land, but not to fight with him.
How could Moshe send to Sichon a message of peace after Hashem had commanded him to go and fight?
Rashi: Moshe learned from Hashem that it is correct to offer peace terms. Refer to 2:26:2:1 & 2. 1
Ramban: Although this Pasuk is written after Hashem's command in Pasuk 24, 2 it preceded it chronologically. 3
Moshav Zekenim (in Pasuk 29): He did so [to avoid] Chilul Hashem.
Oznayim la'Torah: Refer to 2:26:2:5.
Devarim Rabah (Shoftim 5)
