Contradiction with Matthew 7:1
Joel 3:13 speaks of judgment while Matthew 7:1 teaches not to judge others.
Matthew 7:1: Judge not, that ye be not judged.
Contradiction with Matthew 5:9
Joel 3:13 evokes a scene of conflict and judgment, in contrast to Matthew 5:9 which blesses peacemakers.
Matthew 5:9: Blessed [are] the peacemakers: for they shall be called the children of God.
Contradiction with James 2:13
Joel 3:13 emphasizes judgment and harvest of wrath, whereas James 2:13 emphasizes mercy over judgment.
James 2:13: For he shall have judgment without mercy, that hath shewed no mercy; and mercy rejoiceth against judgment. [rejoiceth: or, glorieth]
Contradiction with 1 John 4:8
Joel 3:13 depicts a scene of divine judgment, whereas 1 John 4:8 declares that God is love, suggesting a different aspect of God's nature.
1 John 4:8: He that loveth not knoweth not God; for God is love.
Contradiction with Ezekiel 18:23
Joel 3:13 portrays a scene of judgment, but Ezekiel 18:23 shows God's lack of pleasure in the death of the wicked.
Ezekiel 18:23: Have I any pleasure at all that the wicked should die? saith the Lord GOD: [and] not that he should return from his ways, and live?
Contradiction with Isaiah 2:4
Joel 3:13 anticipates a gathering for judgment, while Isaiah 2:4 speaks of nations beating swords into plowshares and studying war no more.
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]