This is said in reference to those who are victorious to their hurt. Some say that [this is because] after their victory the Thebans were defeated by the Epigonoi; others [say it is because] when Oedipus solved the riddle he married his mother as his prize. It is applied also to deeds which are unprofitable. As he himself said[1] who wrote a history of Thebes, when Cadmus destroyed the dragon which guarded the spring of Ares, he laboured for Ares for eight years.