It is important to note that this third ode comes straight after Antigone and Ismene have been arrested by Creon and it is clear the he plans to have Antigone killed for her crime of disobeying his edict and rule. Even though Antigone is Creon's son's bride, this will not stop him. The Chorus therefore begins by a meditation on how punishment from the gods an go on down through the generations of one particular family, as it clearly has done with the family of Oedipus. The Chorus uses a simile to describe this effect:
For others, once
the gods have rocked a house to its foundations
the ruin will never cease, cresting on and on
from one generation on throughout the race
like a great mounting tide
drive on by savage northern gales...
The Chorus then comments that "the light, the hope" that had sprung up from the house of Oedipus is likewise going to suffer a similar destruction as Oedipus did, being "cut down in turn" by the "long, bloody knife" wielded by the gods of death "in a senseless world."
However, the next stanza goes on to praise Zeus for his power and might. He is so omnipotent that once he has decreed the fate of someone nothing can stop it. Ruin, if it has been decreed on someone, is inevitable, and whilst they may be able to ignore this for a while by their dreams and high hopes, in the end, inexorable fate will work its course and they will fall, just like Oedipus, just like Antigone is about to fall and just like so many others throughout history have fallen.