Why does the Torah not tell us the name of the king of Edom, like it did with regard to the two kings of the Emori (Sichon and Og)?
Ramban: Because the Torah mentions only the names of those kings that are renowned for their might, to enable us to thank Hashem for His miracles in allowing us to conquer them. 1
Ramban: See Tehilim, 136:17-20. And so we find in connection with the kings of Cana'an, where the Pesukim in Yehoshu'a 10:3 and 11:1 mention the particularly strong kings by name, whereas the others it lists without mentioning their names.
Why does the Torah write here that Moshe sent messengers to the king of Edom, whereas later, in 21:21, when they sent messengers to Sichon, it attributed the sending to Yisrael?
Refer to 21:21:1:1.
Why does the Torah need to mention that Moshe sent messengers from Kadeish?
Oznayim la'Torah: To stress the Midos of Moshe, that although it was Kadeish that it was decreed that he would not enter Eretz Cana'an - the land that he so desired to see - it did not deter him from continuing uninterrupted with the preparations concerning Yisrael's entery into Eretz Yisrael and its conquest. 1
See Oznayim la'Torah.
Why did Moshe insert the word "Ko Amar Achicha Yisrael"?
Why did Moshe refer to the hardships that Yisrael endured?
Rashi: To remind Edom that their grandfather Eisav had deliberately moved away "Mipnei Ya'akov Achiv" (Bereishis 36:10), due to the 'debt' which lay upon them both, and he imposed it on Ya'akov alone. 1
Oznayim la'Torah: And he added "Vaneishev be'Mitzrayim Yamim Rabim" (in Pasuk 15), - implying both a long time and days of affliction - see Sh'mos, 2:23 - a hint that he need not regret having escaped paying the debt.
