וְאֶת־הָעָם֮ צַ֣ו לֵאמֹר֒ אַתֶּ֣ם עֹֽבְרִ֗ים בִּגְבוּל֙ אֲחֵיכֶ֣ם בְּנֵי־עֵשָׂ֔ו הַיֹּשְׁבִ֖ים בְּשֵׂעִ֑יר וְיִֽירְא֣וּ מִכֶּ֔ם וְנִשְׁמַרְתֶּ֖ם מְאֹֽד׃
Y manda al pueblo, diciendo: Pasando vosotros por el término de vuestros hermanos los hijos de Esaú, que habitan en Seir, ellos tendrán miedo de vosotros; mas vosotros guardaos mucho:
Rashi
ונשמרתם מאד TAKE YE GOOD HEED TO YOURSELVES — And what is this "taking heed”? What follows: אל תתגרו בם CONTEND NOT WITH THEM.
Chizkuni
ואת העם צו לאמר, “and command the people as follows:” Moses explains the warning here which he had failed to explain in Parshat Chukat. On the other hand, he does not repeat the details of the request in Numbers 20,1421.
Ramban
YOUR BRETHREN THE CHILDREN OF ESAU. The reason for this expression is that descent of Israel is from Abraham and all his seed are thus “brothers” because they were all circumcised. This is the purport of the verse, Thou shalt not abhor an Edomite, for he is ‘thy brother.’124Further, 23:8. Only the sons of the concubines125Genesis 25:6. [of Abraham], Ishmael, Midian126Ibid., Verse 2. and all children of Keturah127Ibid., Verses 1-4. are not in this “brotherhood,” as we see from the verse, for in Isaac shall seed be called to thee.128Ibid., 21:12. Thus Esau [Edom] is in this “brotherhood” for he is a son of Isaac, but Ishmael, born of Hagar and Midian, born of Keturah, although they are Abraham’s biological sons, are not in this “brotherhood,” for as G-d said to Abraham: in Isaac shall seed be called to thee. This makes it clear that the spiritual brotherhood of the Abrahamitic seed is restricted to descendants of Isaac. See my Hebrew commentary p. 351.