Contradiction with Proverbs 3:5
Joshua 8:5 involves using one's own understanding for military strategy, which contradicts trusting in the Lord with all one's heart and not leaning on one's own understanding.
Proverbs 3:5: Trust in the LORD with all thine heart; and lean not unto thine own understanding.
Contradiction with Matthew 5:44
Joshua 8:5 concerns preparing for a military ambush, contradicting the teaching to love your enemies and pray for those who persecute 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 Romans 12:17
Joshua 8:5 involves planning a military ambush, contradicting the call not to repay anyone evil for evil but to do what is right in the eyes of everyone.
Romans 12:17: Recompense to no man evil for evil. Provide things honest in the sight of all men.
Contradiction with Exodus 20:13
Joshua 8:5 involves a plan that would result in killing, contradicting the commandment "Thou shalt not kill."
Exodus 20:13: Thou shalt not kill.
Contradiction with Matthew 26:52
Joshua 8:5 describes a preparation for armed conflict, contradicting the admonition that those who live by the sword will die by the sword.
Matthew 26:52: Thinkest thou that I cannot now pray to my Father, and he shall presently give me more than twelve legions of angels?
Contradiction with James 4:1
Joshua 8:5 involves military engagement, which contradicts the idea that wars and fighting come from selfish desires that battle within.
James 4:1: From whence [come] wars and fightings among you? [come they] not hence, [even] of your lusts that war in your members? [fightings: or, brawlings] [lusts: or, pleasures]