The end of Oedipus at Colonus basically sets up the next play in the series, Antigone. The play ends with the Chorus approving of Antigone’s and Ismene’s decision to go back to Thebes to try to sort out the fight between their brothers: “For in every way, these things are sanctioned” (1779).
The family has been plagued by lawlessness, whether it was intentional or not, so the fact that the Chorus says that the girls’ action is “sanctioned” means they’re finally on the right side of the law. It’s about time, if you ask us.