Contradiction with Matthew 5:44
Joshua 10:38 describes a military conquest and destruction, whereas Matthew 5:44 teaches to love your enemies and bless 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
The commandment "Thou shalt not kill" in Exodus 20:13 seems to contradict the acts of warfare depicted in Joshua 10:38.
Exodus 20:13: Thou shalt not kill.
Contradiction with Isaiah 2:4
Isaiah speaks of turning swords into plowshares and learning war no more, in contrast to the warfare described in Joshua 10:38.
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 Romans 12:19
Romans advises against vengeance, yet Joshua 10:38 depicts acts of retribution through warfare.
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.
Paradox #1
The contradiction or conflict in this context could be the idea of divine commands being used to justify acts of violence or warfare. Some might find it challenging to reconcile actions described as divinely sanctioned that appear to conflict with contemporary ethical standards of peace and non-violence.