Contradiction with Acts 10:28
This verse shows Peter acknowledging that it is unlawful for a Jew to associate with Gentiles, which contrasts with the acceptance of Gentiles in Acts 11:1.
Acts 10:28: And he said unto them, Ye know how that it is an unlawful thing for a man that is a Jew to keep company, or come unto one of another nation; but God hath shewed me that I should not call any man common or unclean.
Contradiction with Matthew 10:5-6
Jesus instructs his disciples to avoid Gentiles and focus on the lost sheep of Israel, while Acts 11:1 speaks of Gentiles receiving the word of God.
Matthew 10:5-6: These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into [any] city of the Samaritans enter ye not:
Contradiction with Galatians 2:12
Peter initially withdrew from eating with Gentiles due to pressure from certain Jews, contradicting the acceptance of Gentiles noted in Acts 11:1.
Galatians 2:12: For before that certain came from James, he did eat with the Gentiles: but when they were come, he withdrew and separated himself, fearing them which were of the circumcision.