פירוש על במדבר 20:18

פן בחרב אצא לקראתך LEST I COME OUT AGAINST THEE WITH THE SWORD — You pride yourselves on the “voice” which your father bequeathed you as a blessing, saying, “And we cried unto the Lord and He heard our voice” (cf. Rashi on v. 16); I, therefore, will come out against you with that which my father bequeathed me when he said, (Genesis 27:40) “And by thy sword shalt thou live” (Midrash Tanchuma, Beshalach 9 on בשלח)

פן בחרב אצא לקראתך, most of the people of Edom were bloodthirsty people and did not need more than the slightest pretext in order to start a war.

ויאמר אליו אדום, “Edom said to him, etc.” The Torah no longer adds the title “king” when speaking of Edom, indicating that the whole nation concurred with their King’s refusal to allow the Israelites passage through their country.

לא תעבור בי, “You will not pass through me!” He meant his country (political entity). The King referred to the direct route to the land of Canaan. Neither he nor his people made any attempt to hinder the progress of the Israelites when they straddled his country marching around it through the region known as Mount Seir. This is why Moses referred to this in a positive sense when he said in Deut. 2,29: “as did for me the sons of Esau who dwell in the Mountain of Seir.” When the Israelites asked permission from Sichon, King of the Emorites, to pass through his land they meant “in the same way as we passed through the land of Edom.” I will elaborate on this theme when we discuss that passage.

With my forefather’s legacy. For if not so, why mention the sword. He should have said, “I will go out against you to war.”

לא תעבור בי, “do not trespass on anything that I own; even though the Israelites offered to pay the King of Edom a head tax for every Israelite who would use the King’s highway, a huge income for him, the King refused adamantly. He was afraid that the Israelites would use the opportunity to invade and conquer his Kingdom.