The Old Testament ceremonial laws (not eating certain meats, not mixing fabrics, animal sacrifices, the tabernacle, etc.) were temporary, as they were symbolic of Jesus Christ, they were a shadow of things to come. They were done away with under the New Covenant when Christ fulfilled them. But the moral laws such as “Thou shalt not kill
This is a huge part of why I dislike the Polemic explanation for canonicity. You can’t make the entirety of scripture revolve around intertestamental Jewish scholars thumbing their noses at Greek culture without abandoning the larger themes and purposes entirely. The vast majority of events documented in the Old Testament predate even the earliest Greek history.