I like how Paul puts the new covenant:
Rom 2:13 (For not the hearers of the law are just before God, but the
doers of the law shall be justified.
Rom 2:14 For when the Gentiles, which have not the law,
do by nature the things contained in the law, these, having not the law, are a law unto themselves:
Rom 2:15 Which
shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another
They do by nature the things contained in the law. Its clear which law is being spoken of For Paul goes on about the 10 commandments.