Contradiction with Joshua 6:2
Illustrates God directly assuring victory against enemies, whereas Joshua 8:6 involves an ambush plan requiring deception for success.
Joshua 6:2: And the LORD said unto Joshua, See, I have given into thine hand Jericho, and the king thereof, [and] the mighty men of valour.
Contradiction with Deuteronomy 20:8
Allows men who are fearful or fainthearted not to fight, contrary to Joshua 8:6 where those with such feelings are integral to the ambush plan.
Deuteronomy 20:8: And the officers shall speak further unto the people, and they shall say, What man [is there that is] fearful and fainthearted? let him go and return unto his house, lest his brethren's heart faint as well as his heart. [faint: Heb. melt]