The overall intention of the prophecies from the oracles is to set the characters on a "path" which will cause them to ultimately discover their destiny.
However, in both the Matrix and Oedipus Rex all of the oracles' prophecies came true. No matter how hard the characters attempted to fight it, their destiny was inescapable. This is true as seen in both stories where the characters' fates in each story were predicted; all of which came true. In Oedipus Rex, all prophecies came true as Jocasta tells Oedipus "There came to Laius once an oracle that his fate was fixed by his son's hand to fall-his own and mine" (line 740). Where it was later realized that it was indeed Oedipus who had killed Laius as well as being his son. As well as in The Matrix, where the Oracle says "You're going to have to make a choice. In one hand, you'll have Morpheus' life and in the other hand, you'll have your own. One of you is going to die Which one.will be up to you." (When Neo meets Oracle) and that "Sorry, kid you got the gift, but it looks like you're waiting for something Your next life maybe, who knows?" (When Neo meets Oracle) Which in the end of the film, Neo does in fact die saving Morpheus only to come back to life as the chosen one. Although every prophecy that is mentioned in either story eventually turned out to be correct, it was ultimately the characters' choices that lead them to their fate.
While it appears that every event in both the Matrix and Oedipus Rex was predetermined, the characters really had the power to go against the Oracles' predictions. As it was their choices that ultimately shaped their destiny. In Oedipus Rex, when Oedipus is told that "he will murder his father and lay with his mother." Rather than attempting of staying in Corinth with his family and attempt to ignore the prophecy, he runs away to Thebes. It is in Thebes where he murders his father and weds his own mother.