Contradiction with John 8:44
This verse mentions that some people speak lies because they are of their father the devil, while John 3:33 indicates acceptance of God's truth.
John 8:44: Ye are of [your] father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. [of his own: or, from his own will or disposition]
Contradiction with Jeremiah 17:9
Speaks to the deceitfulness of the heart, whereas John 3:33 suggests someone accepts and acknowledges God's truth.
Jeremiah 17:9: The heart [is] deceitful above all [things], and desperately wicked: who can know it?
Contradiction with Romans 3:10
States that no one is righteous, not even one, while John 3:33 implies that those who receive His testimony act with truth.
Romans 3:10: As it is written, There is none righteous, no, not one:
Contradiction with 1 John 1:8
Claiming not to have sin contradicts acknowledging God's truth as mentioned in John 3:33.
1 John 1:8: If we say that we have no sin, we deceive ourselves, and the truth is not in us.
Contradiction with Matthew 7:21
Emphasizes that not everyone who calls on the Lord will enter the kingdom, potentially contradicting the acceptance of truth in John 3:33.
Matthew 7:21: Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.