And the meaning is that you used to hide behind walls and veils when committing immoral acts. Your hiding was not out of fear that your limbs would testify against you, because you were not acting according to their testimony against you. Rather, you were denying resurrection and recompense altogether. However, you only hid because you thought that Allah does not know much of what you were doing, which is the hidden aspects of your actions. And that saying, 'And that thought is what has destroyed you,' is indeed true. This serves as a reminder that it is the right of a believer not to let go of, nor to forget, that he has over him a watcher and a guardian from Allah, so that he should be more fearful and more modest in his private moments with his Lord, and more cautious and protective of himself than when he is among people. He should not be careless in his private moments, fearing to resemble those who have such thoughts. It has been read: 'But you claimed,' and 'that thought' is raised as a subject, while 'your thought' and 'has destroyed you' are two predicates. It is also possible that 'your thought' is a substitute for 'that' and 'has destroyed you' is the predicate.