Deuteronomy 2:31

And the Lord said unto me, Behold, I have begun to give Sihon and his land before thee: begin to possess, that thou mayest inherit his land.

Cross-reference

In Deuteronomy 2:24, the same command to begin taking possession of Sihon's land is given—this verse repeats that charge.

In Deuteronomy 1:8, the general command to possess the land is given; here it is applied specifically to Sihon's territory.

In Deuteronomy 4:38, God's pattern of driving out nations to give their land to Israel is described—mirroring Sihon's dispossession.

Numbers 21:24 Historical context

In Numbers 21:24, the fulfillment of this promise is recorded: Israel defeats Sihon and takes his land.