Contradiction with 1 Corinthians 1:18
John 3:11 speaks of the testimony being certain and true, while 1 Corinthians 1:18 refers to the message of the cross being foolishness to those who are perishing.
1 Corinthians 1:18: For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God.
Contradiction with 1 Corinthians 2:14
John 3:11 is about speaking of what is known and seen as true, whereas 1 Corinthians 2:14 claims the natural person does not accept the things of the Spirit of God, implying a disconnect in understanding.
1 Corinthians 2:14: But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know [them], because they are spiritually discerned.
Contradiction with 2 Corinthians 4:3-4
In John 3:11, the testimony of Jesus is clear, but 2 Corinthians 4:3-4 talks about the gospel being veiled to those who are perishing, suggesting a contradiction regarding who receives the message.
2 Corinthians 4:3-4: But if our gospel be hid, it is hid to them that are lost:
Contradiction with John 8:43-45
John 3:11 emphasizes speaking the truth, but John 8:43-45 shows a lack of understanding and acceptance of Jesus’ words, highlighting unbelief and rejection of the truth.
John 8:43-45: Why do ye not understand my speech? [even] because ye cannot hear my word.
Contradiction with Matthew 11:25
John 3:11 discusses open testimony, yet Matthew 11:25 suggests that certain truths are hidden from the wise and revealed only to little children.
Matthew 11:25: At that time Jesus answered and said, I thank thee, O Father, Lord of heaven and earth, because thou hast hid these things from the wise and prudent, and hast revealed them unto babes.
Contradiction with Isaiah 6:9-10
John 3:11's emphasis is on communication of known truths, contradictory to Isaiah 6:9-10, which describes people hearing but not understanding, seeing but not perceiving.
Isaiah 6:9-10: And he said, Go, and tell this people, Hear ye indeed, but understand not; and see ye indeed, but perceive not. [indeed, but understand: or, without ceasing, etc: Heb. in hearing, etc]
Contradiction with Acts 28:26-27
John 3:11 suggests clarity in testimony, while Acts 28:26-27 reflects on people's inability to understand and perceive the message of God.
Acts 28:26-27: Saying, Go unto this people, and say, Hearing ye shall hear, and shall not understand; and seeing ye shall see, and not perceive:
Contradiction with Romans 11:8
John 3:11 speaks of witnessing and testifying, but Romans 11:8 talks about God giving people a spirit of stupor, so they do not see or hear the truth.
Romans 11:8: (According as it is written, God hath given them the spirit of slumber, eyes that they should not see, and ears that they should not hear;) unto this day. [slumber: or, remorse]