Contradiction with Hebrews 8:13
Explains that the old covenant is obsolete and replaced by a new one, which may contradict the continuing covenant with descendants mentioned in Isaiah 59:21.
Hebrews 8:13: In that he saith, A new [covenant], he hath made the first old. Now that which decayeth and waxeth old [is] ready to vanish away.
Contradiction with Galatians 3:28-29
Emphasizes unity in Christ and suggests that the promises apply to all who are in Christ, not just Israel's descendants, contrary to Isaiah 59:21's focus on Israel.
Galatians 3:28-29: There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.