Edom.Gen_27:39, Gen_27:40 was not fulfilled until the reign of Joram (2Ki_8:20-23. 2Ch_21:8-10 (compare 1Ki_22:47). From that time they were implacable enemies.
day. Put by Figure of speech Metonymy (of Adjunct) for what happened at the time (App-6). Compare Job_18:20. Hos_1:11. Joe_1:15. Luk_17:22, Luk_17:26; Luk_19:42. 1Co_4:3.
Who said. The reference is to what they said, not to what they did; to the encouragement given to Sennacherib, not to the help given to Nebuchadnezzar. That is what Obadiah, a later prophet, refers to. Isaiah (Hezekiah's contemporary) refers to the earlier words. See Isa_34:6. Here Edom does not go beyond words.
Rase it, rase it. Figure of speech Epizeuxis (App-6) for emphasis. This was said, not done, at that time.