Romans 2:14-15
2:14 For whenever the Gentiles, who do not have the law, do by nature the things required by the law, these who do not have the law are a law to themselves.
2:15 They show that the work of the law is written in their hearts, as their conscience bears witness and their conflicting thoughts accuse or else defend them,
Romans 2:27
2:27 And will not the physically uncircumcised man who keeps the law judge you who, despite the written code and circumcision, transgress the law?