Romans 2:13-15

13For it is not those who hear the law who are righteous before God, but those who do the law will be declared righteous.

14For 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.

15They 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,