Paul says in his epis­tle to the Romans,

Rom. 2:12 All who have sinned with­out the law will also per­ish with­out the law, and all who have sinned under the law will be judged by the law. 13 For it is not the hear­ers of the law who are right­eous before God, but the doers of the law who will be jus­ti­fied.

In the above Paul refers to sin­ful acts, not to some kind of “sin nature”. I have dealt with the idea in another post.

Paul then he continues:

Rom. 2:14 When Gen­tiles who have not the law do by nature what the law requires, they are a law to them­selves, even though they do not have the law. 15 They show that what the law requires {i.e. lov­ing God with one’s whole heart, mind and strength; and lov­ing one’s neigh­bour as him­self) is writ­ten on their hearts, while their con­science also bears wit­ness and their con­flict­ing thoughts accuse or per­haps excuse them 16 on that day when, accord­ing to my gospel, God judges the secrets of men by Christ Jesus.

Notice that Paul is not talk­ing about Gen­tile con­verts who has the Spirit, but about those Gen­tiles who “by nature” do the works of the law. The term “by nature” doesn’t mean “by regen­er­ated nature”, the thought is far from the con­text, Paul is not talk­ing about Gen­tile con­verts who had the Scrip­tures to refer to, but about those who only had their con­science to approve or dis­ap­prove their actions. The Gen­tiles in Paul’s mind are nat­u­rally good, and there are cer­tainly such peo­ple, just as we find them on the pages of the Tanakh.

Is it not a pos­si­bil­ity that the argu­ment is hypo­thet­i­cal, and there are no such peo­ple at all? Well, Paul is set­ting these Gen­tiles up as an exam­ple before the Jews, for accord­ing to him “the doers of the law who will be jus­ti­fied”, and in his exam­ple these Gen­tiles are indeed the “doers of the law”. If such Gen­tiles didn’t exist, Paul doesn’t have an argument.

So these Gen­tiles do the works of the law not because they have the law and thus received train­ing in the law (or they can look up in the law what is right or wrong), but because they have a sen­si­tive con­science. Cer­tainly, God can work through con­science as we see it in Gen. 6, though the term itself is not mentioned:

Gen. 6:3 Then the LORD said, “My spirit shall not abide in {or with} man for ever, for he is flesh, but his days shall be a hun­dred and twenty years.”

God was try­ing to restrain sin in the ancient world by His Spirit, but in the end He gave it up. They were sim­ply obey­ing their own sin­ful desires — they “saw” and “took” as they chose, just as in Gen. 3. But then there is the statement:

Gen. 6:8 But Noah found favor in the eyes of the LORD.

Gen. 7:1 Then the LORD said to Noah, “Go into the ark, you and all your house­hold, for I have seen that you are right­eous before me in this generation.

Noah is an exam­ple of a Gen­tile who by nature, with­out hav­ing the law, did the works of the law, and was, there­fore, counted as right­eous before God. Job is another one, and there are many more.

In the ear­lier post I argued that peo­ple need train­ing in right­eous­ness. What was said here doesn’t con­tra­dict it. There are peo­ple who are nat­u­rally good. All oth­ers need train­ing. We may elab­o­rate more on this in another post