Deuteronomy 4:46
On this side Jordan, in the valley over against Beth–peor, in the land of Sihon king of the Amorites, who dwelt at Heshbon, whom Moses and the children of Israel smote, after they were come forth out of Egypt:
Cross-reference
Deuteronomy 4:47 continues the conquest narrative, describing the land of Sihon and Og — the same geographical context for the law given here.
Deuteronomy 1:4 summarizes the same defeat of Sihon at Heshbon, setting the historical context for Moses' speech here.
Deuteronomy 1:5 also places Moses declaring the law 'on this side Jordan' in Moab — the same setting as the testimonies given here.
Deuteronomy 2:30-36 narrates the full battle against Sihon, providing the details of the victory referenced here.
Deuteronomy 3:8 describes taking the land of both Amorite kings east of the Jordan, expanding on the conquest mentioned here.
Deuteronomy 3:29 already placed Israel 'in the valley over against Beth-peor' — the same location where Moses later speaks the law in this passage.
Numbers 21:21-32 is the original account of Israel's victory over Sihon, the event Moses recalls in this verse.
Numbers 32:19 shows the Reubenites and Gadites claiming this very land east of the Jordan as their inheritance, directly linking the conquest to settlement.
Joshua 13:20 lists Beth-peor among towns allotted to Reuben, confirming the geographic reference in this verse.