Contradiction with Joshua 6:21
Joshua 8:33 describes a peaceful assembly, while Joshua 6:21 recounts the destruction of every living thing in Jericho.
Joshua 6:21: And they utterly destroyed all that [was] in the city, both man and woman, young and old, and ox, and sheep, and ass, with the edge of the sword.
Contradiction with Matthew 5:9
Joshua 8:33 shows Israelites gathered for a covenant, whereas Matthew 5:9 emphasizes the blessing of peacemakers.
Matthew 5:9: Blessed [are] the peacemakers: for they shall be called the children of God.
Contradiction with Matthew 5:39
In Joshua 8:33, Israelites stand armed for war, while Matthew 5:39 encourages turning the other cheek.
Matthew 5:39: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
Contradiction with Isaiah 2:4
Joshua 8:33 involves warlike preparation, contrary to Isaiah 2:4's vision of turning swords into plowshares.
Isaiah 2:4: And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more. [pruninghooks: or, scythes]
Contradiction with 1 Samuel 15:3
Joshua 8:33's assembly contrasts with the command in 1 Samuel 15:3 to completely destroy the Amalekites.
1 Samuel 15:3: Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass.