In the Oedipus plays, there exists a sort of obscurity between the past, present and future. The past (at least in Oedipus the King), is relatively unknown to the reader, and the future, which is revealed through a series of cryptic prophecies made by Tiresias, the blind Prophet. In Oedipus the King, Oedipus is unsure of the identity of the man he struck down at the crossroads. Furthermore, the time that has passed since he became king is not clearly defined.
This idea of time and the obscurity its passing brings appears to be a major motif within Oedipus the King. In the Oedipus at Colonus Introduction, it summarizes an event in which Theseus, king of Athens, tells the blind and broken Oedipus that time can destroy all alliances and that nothing short of a god can truly be sure of the future. This is likely a continuation of the theme started in Oedipus the King. In any case, “the obscurity of time” is a prevalent and often occurring motif that most likely communicates a larger, more overbearing theme that is worth taking note of as we continue to read.