In lines 101-105, Creon states to Oedipus:
Then let me report what I heard from the god.
Lord Phoebus clearly orders us to drive away
the polluting stain this land has harboured—
which will not be healed if we keep nursing it.
Apollo, the Greek god of health, is responsible for the plague that has befallen Thebes (note: Phoebus is another name for Apollo). When Creon describes "what he heard from the god", he is stating that he has consulted an oracle and is bearing its message. The "polluting stain" refers to the Greek concept of miasma, that a certain type of ritual pollution renders not just the individual evildoer liable to divine punishment, but pollutes his or her entire family, and in cases of royal families, the extended household that is the polis. Thus Apollo has decreed that the source of miasma must be driven away in order for the plague to end.