Contradiction with Matthew 15:24
Jesus states he was sent only to the lost sheep of Israel, contrasting with the new inclusion of Gentiles in Acts 10:1.
Matthew 15:24: But he answered and said, I am not sent but unto the lost sheep of the house of Israel.
Contradiction with Deuteronomy 7:2
God commands not to make covenants with certain non-Israelite peoples, while Acts 10:1 begins the story of a Gentile being accepted.
Deuteronomy 7:2: And when the LORD thy God shall deliver them before thee; thou shalt smite them, [and] utterly destroy them; thou shalt make no covenant with them, nor shew mercy unto them: