Contradiction with Galatians 1:1
Paul emphasizes his apostolic authority as directly from Jesus Christ and God the Father, rather than being addressed to a specific group, contrasting the communal address in Colossians 1:2.
Galatians 1:1: Paul, an apostle, (not of men, neither by man, but by Jesus Christ, and God the Father, who raised him from the dead;)
Contradiction with 1 Corinthians 1:2
Paul addresses this letter to all who call upon Jesus in every place, which includes a broader audience than the faithful brethren specified in Colossians 1:2.
1 Corinthians 1:2: Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called [to be] saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:
Contradiction with John 8:15
Jesus states that He judges no one, contrasting with the notion of saints in Colossians 1:2, which implies a judgment or selection of holy individuals.
John 8:15: Ye judge after the flesh; I judge no man.
Contradiction with Romans 8:7
Indicates the carnal mind is enmity against God, contradicting the notion of peace from God mentioned in Colossians 1:2.
Romans 8:7: Because the carnal mind [is] enmity against God: for it is not subject to the law of God, neither indeed can be. [the carnal...: Gr. the minding of the flesh]
Contradiction with Luke 10:5-6
Describes peace resting on the sons of peace if found, suggesting peace is conditional, in contrast to the peace wished directly to someone in Colossians 1:2.
Luke 10:5-6: And into whatsoever house ye enter, first say, Peace [be] to this house.
Contradiction with Matthew 10:34
Jesus claims He did not come to send peace, contrary to the peaceful greeting of Colossians 1:2.
Matthew 10:34: Think not that I am come to send peace on earth: I came not to send peace, but a sword.
Contradiction with James 4:4
Declares the friendship of the world is enmity with God, contradictory to saints being part of the world as addressed in Colossians 1:2.
James 4:4: Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God.