Contradiction with Matthew 5:44
Joshua 6:8 describes a military procession and actions leading to a conquest, while Matthew 5:44 teaches love for enemies and blessing those who curse you.
Matthew 5:44: But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
Contradiction with Exodus 20:13
Joshua 6:8 is part of a narrative leading to warfare, whereas Exodus 20:13 commands, "Thou shalt not kill."
Exodus 20:13: Thou shalt not kill.
Contradiction with Romans 12:19
Joshua 6:8 involves instructions for an attack, whereas Romans 12:19 advises against seeking personal vengeance, advocating for peace.
Romans 12:19: Dearly beloved, avenge not yourselves, but [rather] give place unto wrath: for it is written, Vengeance [is] mine; I will repay, saith the Lord.
Contradiction with Isaiah 2:4
Joshua 6:8 is centered on warfare, while Isaiah 2:4 envisions a future without war, where nations beat 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 James 3:17
Joshua 6:8 involves tactical obedience for warfare, whereas James 3:17 emphasizes wisdom from above, which is "peaceable, gentle, and easy to be intreated."
James 3:17: But the wisdom that is from above is first pure, then peaceable, gentle, [and] easy to be intreated, full of mercy and good fruits, without partiality, and without hypocrisy. [partiality: or, wrangling]