Contradiction with Deuteronomy 28:15
Isaiah 1:19 promises blessings for obedience, while Deuteronomy 28:15 warns of curses if commandments are not followed.
Deuteronomy 28:15: But it shall come to pass, if thou wilt not hearken unto the voice of the LORD thy God, to observe to do all his commandments and his statutes which I command thee this day; that all these curses shall come upon thee, and overtake thee:
Contradiction with Romans 6:14
Isaiah 1:19 implies blessings through obedience to the law, whereas Romans 6:14 emphasizes freedom from the law through grace.
Romans 6:14: For sin shall not have dominion over you: for ye are not under the law, but under grace.
Contradiction with Galatians 2:16
Isaiah 1:19 suggests blessings through obedience, but Galatians 2:16 states that justification comes not by works of the law, but through faith in Jesus Christ.
Galatians 2:16: Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.
Contradiction with Ecclesiastes 9:11
Isaiah 1:19 implies success through willingness and obedience, while Ecclesiastes 9:11 suggests that time and chance might influence outcomes irrespective of one's efforts.
Ecclesiastes 9:11: I returned, and saw under the sun, that the race [is] not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favour to men of skill; but time and chance happeneth to them all.
Contradiction with Matthew 5:45
Isaiah 1:19 indicates rewards for obedience, yet Matthew 5:45 explains that God causes the sun to rise on the evil and the good, suggesting that blessings come to all regardless of their actions.
Matthew 5:45: That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.
Contradiction with John 1:17
Isaiah 1:19 is centered on blessings through law adherence, whereas John 1:17 contrasts the law with grace and truth brought by Jesus Christ.
John 1:17: For the law was given by Moses, [but] grace and truth came by Jesus Christ.
Contradiction with Proverbs 22:16
Isaiah 1:19 promises prosperity through obedience, but Proverbs 22:16 warns that oppressing the poor or giving to the rich leads to poverty, unrelated to obedience to God.
Proverbs 22:16: He that oppresseth the poor to increase his [riches, and] he that giveth to the rich, [shall] surely [come] to want.