During the course of Sophocles' Oedipus Rex, the chorus reacts to the various situations in which Oedipus and the other characters find themselves. This is not surprising and happens, I would dare to say, in all Greek plays.
When the Theban elders enter, they are fearful for the fate of their city. In their initial interaction with Oedipus, they serves as providers of information about Laius' killer.
After Oedipus' heated exchange with Teiresias, the Theban elders are "confused" and their "hopes flutter here and there" (Ian Johnston translation). They are shaken by Teiresias' words, but they still believe that Oedipus "he never will be guilty of a crime".
The Theban elders' concerns become deeper following Oedipus' accusations against Creon. They are troubled by Oedipus' accusations. As the play continues, their attitude towards their king appears further shaken as they declare that "Insolence gives birth to tyranny".
Once Oedipus discovers the truth about his identity, the chorus responds with both pity and horror at what has happened to their king. They acknowledge that they had "honoured [him] above all other men", but they also wish that they had never seen him.