Rom 2:1-4
"Therefore you have no excuse, O man, every one of you who judges. For in passing judgment on another you condemn yourself, because you, the judge, practice the very same things."
The rhetorical diatribe: Paul addresses the moralist who agreed with the condemnation in chapter 1. God's kindness (chrestotes), tolerance (anoche), and patience (makrothymia) are invitations to repentance, not approval of sin.
Rom 2:14-16
"For when Gentiles, who do not have the law, by nature do what the law requires, they are a law to themselves, even though they do not have the law."
Natural law and conscience (syneidesis): the Gentiles have the work of the law written on their hearts. Conscience does not save — it condemns, because no one obeys it perfectly. Biblical basis for natural law and universal moral responsibility.