Contradiction with Matthew 5:17
Jesus states that he has come to fulfill the law, which might suggest adherence to it, potentially conflicting with the notion of Acts 15:15 that the apostles and elders conclude certain laws shouldn't bind Gentile believers.
Matthew 5:17: Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
Contradiction with Galatians 5:3
Here, Paul emphasizes the obligation to keep the whole law if one receives circumcision, conflicting with Acts 15:15's implication that such legalistic requirements aren't necessary.
Galatians 5:3: For I testify again to every man that is circumcised, that he is a debtor to do the whole law.
Contradiction with Romans 3:31
Paul argues that faith does not nullify the law but establishes it, which could be seen as at odds with Acts 15:15 dismissing certain legal requirements for Gentiles.
Romans 3:31: Do we then make void the law through faith? God forbid: yea, we establish the law.
Contradiction with Matthew 28:19-20
Jesus commands teaching 'all things' he has commanded, possibly extending Jewish law observance contrary to Acts 15:15's relaxed view.
Matthew 28:19-20: Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: [teach...: or, make disciples, or, Christians of all nations]
Contradiction with James 2:10
Suggests that breaking one law means being guilty of all, which emphasizes strict adherence to the law, differing from the allowance for Gentiles in Acts 15:15.
James 2:10: For whosoever shall keep the whole law, and yet offend in one [point], he is guilty of all.