Contradiction with Matthew 5:9
"Blessed are the peacemakers: for they shall be called the children of God." contrasts with the call to battle readiness in Jeremiah 51:12.
Matthew 5:9: Blessed [are] the peacemakers: for they shall be called the children of God.
Contradiction with Isaiah 2:4
Prophecy of turning swords into plowshares contrasts the preparation for war urged in Jeremiah 51:12.
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 Jeremiah 29:7
"Seek the peace of the city..." contrasts the call for battle against Babylon in Jeremiah 51:12.
Jeremiah 29:7: And seek the peace of the city whither I have caused you to be carried away captives, and pray unto the LORD for it: for in the peace thereof shall ye have peace.
Contradiction with Romans 12:18
"If it be possible, as much as lieth in you, live peaceably with all men." contradicts preparing for conflict as seen in Jeremiah 51:12.
Romans 12:18: If it be possible, as much as lieth in you, live peaceably with all men.