▼ The presence of the article does not mean that he was to write this in a book that was existing now, but in one dedicated to this purpose (book, meaning scroll). See GKC 408 #126.s.

▼ The Hebrew word is “place,” meaning that the events were to be impressed on Joshua.

▼ Heb “in the ears of Joshua.” The account should be read to Joshua.

▼ The construction uses the infinitive absolute and the imperfect tense to stress the resolution of Yahweh to destroy Amalek. The verb מָחָה (makhah) is often translated “blot out” – but that is not a very satisfactory image, since it would not remove completely what is the object. “Efface, erase, scrape off” (as in a palimpsest, a manuscript that is scraped clean so it can be reused) is a more accurate image.

▼ This would seem to be defeated by the preceding statement that the events would be written in a book for a memorial. If this war is recorded, then the Amalekites would be remembered. But here God was going to wipe out the memory of them. But the idea of removing the memory of a people is an idiom for destroying them – they will have no posterity and no lasting heritage.