Contradiction with Matthew 5:44
While Judges 9:35 involves conflict and possibly violence, Matthew 5:44 advocates for loving enemies and praying 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 Exodus 20:13
Judges 9:35 is related to the context of battle and killing, whereas Exodus 20:13 directly commands against killing.
Exodus 20:13: Thou shalt not kill.
Contradiction with Romans 12:19
Judges 9:35 is part of a narrative involving human vengeance, but Romans 12:19 instructs believers not to avenge themselves and to leave room for God's wrath.
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 25:21-22
The context of Judges 9:35 supports conflict, in contrast to the advice in Proverbs 25:21-22 which suggests feeding and giving drink to enemies.
Proverbs 25:21-22: If thine enemy be hungry, give him bread to eat; and if he be thirsty, give him water to drink:
Contradiction with Matthew 26:52
The narrative in Judges 9:35 can imply violence, whereas Matthew 26:52 teaches that those who take up the sword will perish by the sword.
Matthew 26:52: Thinkest thou that I cannot now pray to my Father, and he shall presently give me more than twelve legions of angels?