Torah portion Acharei Mot (Lev 16-18) emphasizes that there is only one standard for the native born and for gentiles who join themselves to Israel. So when the Council of Jerusalem in Acts 15 tells gentiles to avoid idols, abstain from sexual immorality, things strangled and blood, they are simply quoting the Torah's requirements that apply to both Jew and gentile. When they say that gentiles need not be circumcised, they are quoting the law of the Passover from Exodus. In their ruling, the council was simply applying Torah correctly to the gentiles. They were not changing the standards.