Contradiction with Deuteronomy 3:11
Joshua 13:21 mentions the kingdom of Og in Bashan, while here it describes Og as the last of the Rephaim, implying the kingdom should not exist.
Deuteronomy 3:11: For only Og king of Bashan remained of the remnant of giants; behold, his bedstead [was] a bedstead of iron; [is] it not in Rabbath of the children of Ammon? nine cubits [was] the length thereof, and four cubits the breadth of it, after the cubit of a man.
Contradiction with Numbers 21:35
Joshua 13:21 discusses the remnants of Sihon’s kingdom, yet this verse states that all were defeated and none remained.
Numbers 21:35: So they smote him, and his sons, and all his people, until there was none left him alive: and they possessed his land.
Contradiction with Deuteronomy 2:34
This verse mentions utterly destroying towns, which contradicts Joshua 13:21 where certain people and cities seem to remain.
Deuteronomy 2:34: And we took all his cities at that time, and utterly destroyed the men, and the women, and the little ones, of every city, we left none to remain: [the men...: Heb. every city of men, and women, and little ones]
Contradiction with Deuteronomy 20:16-17
Joshua 13:21 speaks of the surviving Rephaim, contrary to the complete destruction commanded here.
Deuteronomy 20:16-17: But of the cities of these people, which the LORD thy God doth give thee [for] an inheritance, thou shalt save alive nothing that breatheth:
Contradiction with Joshua 12:4
It implies the defeat of all Bashan under Og, conflicting with Joshua 13:21 where the land is still noted with its heritage.
Joshua 12:4: And the coast of Og king of Bashan, [which was] of the remnant of the giants, that dwelt at Ashtaroth and at Edrei,
Contradiction with Numbers 32:33
The land of Og and Sihon being given to specific tribes contrasts with Joshua 13:21 as it lists cities and kings still acknowledged by another.
Numbers 32:33: And Moses gave unto them, [even] to the children of Gad, and to the children of Reuben, and unto half the tribe of Manasseh the son of Joseph, the kingdom of Sihon king of the Amorites, and the kingdom of Og king of Bashan, the land, with the cities thereof in the coasts, [even] the cities of the country round about.
Contradiction with Judges 11:21-22
This verse claims Israel possessed lands to Arnon, not emphasizing the hereditary rule distinct in Joshua 13:21.
Judges 11:21-22: And the LORD God of Israel delivered Sihon and all his people into the hand of Israel, and they smote them: so Israel possessed all the land of the Amorites, the inhabitants of that country.