Why do the opposite of skillful virtues result in remorse?

> "Skillful virtues have freedom from remorse as their purpose, > Ananda, and freedom from remorse as their reward." > AN 11.1 > It is natural that non-regret arises in a virtuous > person, one whose behavior is virtuous. > AN 10.2 What is the basis for defining skillful virtues, that would result in freedom from remorse? The Abrahamic religions depend on God to define what is right and wrong. The Buddhist suttas define skillful virtues based on "freedom from remorse". The precepts like killing, stealing, adultery and lying result in remorse. **Why do they result in remorse?** I've seen vague explanations based on laws of karma or kamma niyama (Dhp 127), natural laws or principles ("this law of nature persists, this regularity of natural principles, this invariance of natural principles") based on AN 3.136 or SN 12.20, the Golden Rule ("don't do unto others what you don't want others to do unto you") based on Ud 5.1, and linking to the three poisons. However, I have not seen suttas that definitively provide a cause for remorse. Please support with sutta references, as far as possible.