Contradiction with Genesis 1:1
Describes the creation of the world, which contrasts with the specific marching instructions in Joshua 6:13.
Genesis 1:1: In the beginning God created the heaven and the earth.
Contradiction with Exodus 20:13
Prohibits killing, whereas Joshua 6:13 is part of a narrative leading to the battle of Jericho.
Exodus 20:13: Thou shalt not kill.
Contradiction with Leviticus 19:18
Teaches love for your neighbor, in contrast to the acts leading up to the city's conquest in Joshua 6:13.
Leviticus 19:18: Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbour as thyself: I [am] the LORD.
Contradiction with Matthew 5:9
Calls for peacemakers, which contradicts the battle preparedness in Joshua 6:13.
Matthew 5:9: Blessed [are] the peacemakers: for they shall be called the children of God.
Contradiction with Romans 12:17
Instructs not to repay evil for evil, differing from the combative context of Joshua 6:13.
Romans 12:17: Recompense to no man evil for evil. Provide things honest in the sight of all men.
Contradiction with James 3:17
Describes wisdom as peaceable, in contrast to the warlike preparation in Joshua 6:13.
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]