Thematic Bible: The conscience witnessing

(For when the [unconverted] Gentiles, who do not have the law of Moses, instinctively practice [some of] its requirements, they become their own lawmakers, even though they do not have the law of Moses. In doing this [i.e., practicing some of the requirements of the law of Moses], they demonstrate that these requirements are written in their hearts. Their conscience tells them this, and their thoughts alternately accuse them [of wrongdoing], or else endorse them [for doing right]).