In Oedipus the King it is made quite clear by Sophocles that trying to defy your fate is pointless and only results in your fate coming to pass whether you like it or not. The first example of the pointlessness of trying to defy your fate is that of Laius. One day Laius, Oedipus' true father, was confronted by an oracle of Apollo. This oracle said that "doom would strike him down at the hands …showed first 75 words of 789 total…

…showed last 75 words of 789 total…had killed his real father, married his real mother and had children by her. So shamed by this, Jocasta killed herself and then finding his wife/mother dead, Oedipus gouged out his eyes. As it is clear to see in this tale of incest and immorality known as Oedipus the King, trying to defy your fate is an act of stupidity that results only in what you had started out trying to defeat happening anyway.