Romans 2:12-15
2:12 For all who have sinned apart from the law will also perish apart from the law, and all who have sinned under the law will be judged by the law.
2:13 For it is not those who hear the law who are righteous before God, but those who do the law will be declared righteous.
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,