Amphion

Amphion was the son of Jupiter and Antiope, Queen of Thebes. He and his twin brother Zethus grew up as shepherds on Mount Cithaeron. Amphion played the lyre while Zethus hunted.

One day the twins learned of their heritage, and that their mother was being treated cruelly by Lycus, the usurping king of Thebes, and his wife Dirce.

The twins were angry, and with a herd of fellow shephers stormed Thebes, and made bulls drag Dirce by her hair until she died. Amphion became king. It is he said he fortified the walls of the city by playing on his lyre, and all the stones moved of their own accord.

This is a mixture of a story and a myth, and it does not really have a moral except: Don't mistreat the mother of the son of a god, or you'll come to a very painful. Or don't mistreat the mother of anyone, basically, because their son will avenge her.