I don't know how to explain the following quotation and how it can relate to Oedipus the King. "What has the man to fear when life is ruled by chance, and the future is unknowable? The best way is to take life as it comes."
"What has the man to fear when life is ruled by chance, and the future is unknowable? The best way is to take life as it comes."
The quote referenced in your question applies very directly to the tragic elements in Oedipus the King. In the play, Oedipus' parents send him to live with another family in order to prevent the horrific predictions made by the oracle (namely that Oedipus would grow up to marry his mother and murder his father). It is in sending Oedipus away that they make it possible for fate to come true because Oedipus never grows up to be familiar with his mother or father. In this sense, by attempting to tamper with fate rather than taking life as it comes, Oedipus' family allows the entire prophecy to come true. The irony of the situation is that if the family had allowed their lives to play out without intervention it is possible that the story may have turned out differently (Oedipus, knowing Jocasta from childhood, would have had a hard time justifying their marriage).
Philosophically speaking, however, the thematic element remains the same: can one ever take control of one's fate? And moreover, is fate more terrifying if we never know the outcome before it occurs? For Oedipus, it is in knowing the outcome of his life that tragedy transpires.