Romans 2:13-15

13(for not the hearers of the law are just in the sight of God, but the doers of the law will be justified;

14for when Gentiles, who do not have the law, by nature do the things in the law, these, although not having the law, are a law to themselves,

15who show the work of the law written in their hearts, their conscience also bearing witness, and between themselves their thoughts accusing or else excusing them)