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: Romans 2:14
The atheist says “I cant be judged by God because I don’t believe in God” this is a strawman argument, the same as saying “I cant be given a traffic ticket because I don’t believe a cop exists or I don’t believe the traffic laws”
We instinctively know right from wrong, anyone who denies that is either lying or foolish. You know its wrong to murder or rape, you don’t need to be religious to know this. You don’t need a law to tell you murder and rape are wrong, you instinctively know this. If you look at the majority of nations, all would agree rape and murder are wrong
This is what the Apostle Paul was teaching here, the Gentiles didn’t have the Torah “Gods Law” taught to them yet they instinctively know Gods Law. Why? Because God has a moral law that is written in our hearts. Some fail to listen to their conscience while others come to The Lord in true repentance
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;) Romans 2:15
We have a conscience because we have the Law of God written in our hearts. Often when people are guilty of crimes their conscience torments them because they know what their doing is evil. Right and Wrong, Good or Evil is not subjective
Hitler believed he was justified however we know Hitler was evil, why? Because we know the Law of God. If there is no God then there is no Law, then everything would be subjective. But because we know there is a Law of Good and Evil we know God does exist
Listen to your conscience, repent of your sins and believe in the Lord Jesus Christ and you will be saved Amen!