Contradiction with Proverbs 18:21
This verse emphasizes the power of the tongue to bring life or death, which can contradict the calm response of Jesus to accusations of having a devil in John 8:49.
Proverbs 18:21: Death and life [are] in the power of the tongue: and they that love it shall eat the fruit thereof.
Contradiction with Matthew 5:39
This verse advises to turn the other cheek when faced with evil, contradicting with the direct manner in which Jesus confronts the accusation in John 8:49.
Matthew 5:39: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
Contradiction with Romans 12:19
This verse instructs to leave vengeance to God, yet in John 8:49, Jesus directly addresses the insult of having a devil.
Romans 12:19: Dearly beloved, avenge not yourselves, but [rather] give place unto wrath: for it is written, Vengeance [is] mine; I will repay, saith the Lord.
Contradiction with 1 Peter 3:9
This verse advises not to repay evil with evil or insult with insult, which contrasts with Jesus countering the accusation in John 8:49.
1 Peter 3:9: Not rendering evil for evil, or railing for railing: but contrariwise blessing; knowing that ye are thereunto called, that ye should inherit a blessing.
Contradiction with James 1:19
Advises to be slow to speak, while in John 8:49, Jesus quickly responds to the accusation leveled at Him.
James 1:19: Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath: