Contradiction with Matthew 5:44
Judges 20:39 depicts conflict and killing, while Matthew 5:44 advocates for loving enemies and non-violence.
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
Judges 20:39 involves warfare and killing, whereas Exodus 20:13 commands "Thou shalt not kill."
Exodus 20:13: Thou shalt not kill.
Contradiction with Romans 12:19
Judges 20:39 illustrates human vengeance, whereas Romans 12:19 instructs believers to leave vengeance to God.
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
Judges 20:39 involves battle, contrasting with Isaiah 2:4, which envisions a future without war.
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 1:20
Judges 20:39 showcases wrath leading to violence, but James 1:20 states that human anger doesn't produce the righteousness God desires.
James 1:20: For the wrath of man worketh not the righteousness of God.