Or HaChaim on Genesis 15:18/אור החיים על בראשית ט״ו:י״ח

1 ביום ההוא כרת ה׳ את אברם ברית. On that day G'd made a covenant with Abram. The reason that G'd used the past tense in referring to the gift of the land of Israel to Abraham and his descendants is that He had already made Abraham take possession of it, as we explained on 13,15. Abraham's children would henceforth own the land in their capacity as his heirs.

2In view of this clear-cut promise of the Bible that the descendants of Abraham were to inherit the land of the ten nations mentioned, how could Jewish heretics delude themselves by denying that there is hope for us in the future, seeing that G'd's promise had already been fulfilled and we have forfeited it due to our sins?. [I believe the author refers to converts who accept the Christian theologians' views of Jewish history. Ed.] In view of the fact that we never possessed the land of all of these ten nations, the promise of the covenant has clearly not been fulfilled as yet. Up until now Israel only occupied the land belonging to seven of the ten nations listed here. We did not even possess all the land of those seven nations. How then can one understand the people of little faith [the author calls them the dried up bones describing the revelation in Ezekiel 37. Ed.] who have given up on our glorious messianic future? G'd treated us according to the principle of מדה כנגד מדה, that punishment must fit the crime. Seeing that we were supposed to be G'd's servants but rebelled in that we failed to observe many of His commandments, He caused those who were supposed to be our servants to rebel against us. This does not mean that G'd does not have the power to fulfil His covenant in full at the appropriate time.

3The reason that the Torah first lists the nations whose territory we never captured, i.e. the Keyni, the Knizi and the Kadmoni, is that they are only different names for the Ammonites, the Moabites and the Edomites. When the time arrives when we will experience realisation of G'd's promise concerning those three nations, we will also again recapture the lands of the other seven nations listed here at the end. The Torah mentions those three first in order to teach us that the essential element of G'd's promise is that we will dispossess those three nations. The author sees an allusion of the future in Abraham's defeat of the four kings listed in 14,1. Three of them symbolise the Ammonites, Moabites and the Edomites. The last one (of those four), "Tidal king of גוים," represents the other seven nations. [The author seems to feel that the word גוים does not describe the name of a specific nation. Ed.]