Can you be guilty in your thoughts even if you are not guilty overtly?
Yes. Scripture indicates a person may not be guilty overtly but is guilty covertly, especially in the thought processes. The conscience bears witness, and thoughts accuse or excuse, showing the work of the Law written in the heart. This is human nature.
Les explains from Romans 2:14-15 that Gentiles who do not have the Law yet do by nature the things contained in the Law are a law unto themselves. The work of the Law is written in their heart, and their conscience also bears witness. Their thoughts accuse or excuse them. Les teaches that people may not be guilty of something overtly, but they will be guilty covertly, especially in the thought processes. Conscience is where it all begins; God put conscience in Adam, and conscience was to precipitate confession. It convicted Abel and prompted him to bring the required sacrifice. Human nature can spurn or burn conscience until it is no longer active, but it is still there and cannot be ignored.
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;)