How does the author use foreshadowing in Seven against Thebes?

In the first section, Eteocles address to the assembled Cadmeians and his generalizing hostis move rapidly, as will the play, to a focus on his own involvement; his description of the external threat to the city and his commands to the citizens as a group lead to his statement of his own, individual role; the messenger's speech itself moves from description of the invader to injunctions aimed primarily at Eteocles himself; and the messenger's focus on the foreign enemy is answered by Eteocles' emphasis on the native gods and land of Thebes, a movement that foreshadows the play's overall shift of focus from a foreign danger to an indigenous, earth-rooted curse.