Contradiction with Exodus 20:13
John 12:10 describes a plot to kill Lazarus, which contradicts Exodus 20:13's commandment "Thou shalt not kill."
Exodus 20:13: Thou shalt not kill.
Contradiction with Matthew 5:44
John 12:10 involves a plan to harm Lazarus, which contradicts Matthew 5:44's teaching to love your enemies and pray for those who persecute you.
Matthew 5:44: But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
Contradiction with Romans 12:19
John 12:10 involves taking vengeance into human hands, contradicting Romans 12:19's instruction to leave vengeance to God.
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 Proverbs 6:16-17
John 12:10 involves a plot to kill, contradicting the abomination of hands that shed innocent blood mentioned in Proverbs 6:16-17.
Proverbs 6:16-17: These six [things] doth the LORD hate: yea, seven [are] an abomination unto him: [unto...: Heb. of his soul]
Contradiction with Matthew 7:12
John 12:10's context of plotting harm is against the Golden Rule taught in Matthew 7:12 to do unto others as you would have them do to you.
Matthew 7:12: Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.
Contradiction with 1 John 4:20
John 12:10, which involves hatred and plotting murder, is contradictory to 1 John 4:20, which teaches that one cannot love God while hating a brother.
1 John 4:20: If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen?