Contradiction with Exodus 23:32
This verse advises against making covenants with the inhabitants of the land, whereas in Joshua 9:7, the Israelites discuss making a peace agreement with the Gibeonites.
Exodus 23:32: Thou shalt make no covenant with them, nor with their gods.
Contradiction with Deuteronomy 7:2
This verse commands the Israelites to make no covenants and to utterly destroy the people of the land, contrasting with the consideration of an agreement in Joshua 9:7.
Deuteronomy 7:2: And when the LORD thy God shall deliver them before thee; thou shalt smite them, [and] utterly destroy them; thou shalt make no covenant with them, nor shew mercy unto them:
Contradiction with Deuteronomy 20:16-18
These verses instruct the Israelites to leave no survivors in certain cities of the promised land, in contrast to the possibility of making a treaty as seen in Joshua 9:7.
Deuteronomy 20:16-18: 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 Judges 2:2
This verse criticizes the making of covenants with the inhabitants of the land, contradicting the situation in Joshua 9:7 where such a covenant is contemplated.
Judges 2:2: And ye shall make no league with the inhabitants of this land; ye shall throw down their altars: but ye have not obeyed my voice: why have ye done this?