John Gill Commentary Deuteronomy 19:1

"When Jehovah thy God shall cut off the nations, whose land Jehovah thy God giveth thee, and thou succeedest them, and dwellest in their cities, and in their houses;" — Deuteronomy 19:1 (ASV)

When the Lord your God has cut off the nations whose land the
Lord your God gives you
The seven nations of the land of Canaan, whose destruction was of the Lord for their sins, and whose land was a gift of him that had a right to dispose of it to the children of Israel; see (Deuteronomy 12:29)

and you succeed them, and dwell in their cities, and in their
houses ;
should possess their land in their stead, by virtue of the gift of it to them by the Lord, and inhabit their cities and houses built by them.