Ibn Ezra on Numbers 24:18

והיה אדום ירשה. מגזרת ואם לא תורישו והוא שם במשקל קח לך לבנה והוא תחת תאר השם כמו והיתה הארץ שממה ויודע כי גברה יד דוד על אדום והר שעיר: AND EDOM SHALL BE A POSSESSION. The word yereshah (possession) is related to the word torishu (drive out)⁵⁸I.E. renders torishu destroy. See I.E. on Ex. 15:9. in But if ye will not drive out (Num. 33:55).⁵⁹I.E. renders ve-hayah edom yereshah (And Edom shall be a possession) as, and Edom shall be destroyed. Yereshah is a noun vocalized according to the pattern of the word levenah (tile) in take thee a tile (Ezek. 4:1). It is in place of an adjective. Compare the word shemamah (desolation) in and it shall be a desolation (Is. 17:9).⁶⁰Here too Scripture employs a noun (shemamah) in place of an adjective (shomemah). We know that David’s hand overpowered Edom⁶¹See II Sam. 8:14. and Mount Seir.⁶²Edom’s abode.