Rashi on Genesis 15:19/רש"י על בראשית ט״ו:י״ט

1The Kenites. Ten nations are listed here, [yet] He gave to them only [the land] of Seven Nations. The three [whose lands were not given], Edom, Moav, and Ammon which are [referred to here as]: Keini, Knizi, and Kadmoni are destined to be possessed in the future, as it is said: “They will overpower Edom and Moav and the Ammonites will obey them.”