Contradiction with Matthew 5:44
Isaiah 29:7 suggests destruction of enemies, while Matthew 5:44 teaches love for enemies.
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
Isaiah 29:7 implies divine vengeance, whereas Romans 12:19 advises against personal vengeance.
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 Luke 6:27
Isaiah 29:7 involves defeating foes, but Luke 6:27 instructs to do good to those who hate you.
Luke 6:27: But I say unto you which hear, Love your enemies, do good to them which hate you,
Contradiction with Proverbs 25:21-22
Isaiah 29:7 depicts enemies being subdued, while Proverbs 25:21-22 promotes kindness 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: