Paul doesn't really teach that, that has become the understanding of some who misinterpret his old style Greek Koine writings when they got translated into old English.
Firstly, Paul is saying that God predestinated us ALL unto God via Jesus' blood. In other words God foreknew we would all need a savior, thus the words of John in Revelation matches this, Jesus was slain before the foundations of the earth was ever created.
So, predestination is actually a misunderstanding of Paul's teachings.
Secondly, in Romans Paul is trying to teach the Romans that they also can fall just as the Jewish peoples have if they abide NOT IN THE FAITH, but try as the Jews did to serve God via works of the flesh by keeping the Laws which can not save them. (see Gal. 3). So, why is Paul telling the Romans about God choosing whom He will chose? Because as Paul says, that is up to God the Potter what vessel He so chooses, but the mistake that people make is they do not understand this is not about the ELECTION of Salvation, but the Election of Service unto God.
Esau was not HATED that is also a mistranslation, the word actually means LOVED LESS, so God chose Jacob over Esau for SERVICE not predetermined Salvation. God foresaw all events and foreknew Jacob was the one to best fit His plans. I mean DUH, God sees all things right, LOL....He of course chose properly.......because of SERVICE not Election, Esau via FAITH could have still been accepted by God, but not for SERVICE, God chooses whom He will via His own plans !! So, God did not reject Israel, He chose them, but the refused to live Godly, and they chose to submit unto the law over faith. So, God then chose the Gentiles to carry His Gospel unto the whole world. After the Rapture (time of the Gentiles is finished) God will graft Israel back in when they BELIEVE AGAIN, Paul says so in Rom. 11.
So, Romans chapters 9-11 is about Election, not Salvation, Jews could still be saved, Paul was, Stephen was, Mark, Matthew and Peter were, we see Messianic Jews today also. But Israel as a nation was thrown over like Esau was for Jacob for God's own SERVICE PLANS. But WHY? Because of Unbelief AND because eventually Israel would have co-opted Christianity into a more modern form of Judaism if the 70 AD Events had never happened because they loved serving THE LAW more than serving THE FAITH.
So, God foresaw the way to reach the heathen Gentiles was to disciple them via the Disciples, and to then allow them to spread the unvarnished Gospel of Jesus Christ, which is why Paul got angry at the Galatians who were tryin to serve THE LAW instead the FAITH, and he tells them, who has bewitched you that starting out in the faith you are now serving the Flesh (Law)? Then he continues to give them example after example in Gal. 3, and finally he says there is neither Jew nor Greek, male nor female, not because there are not any females or males any longer, or because there will be no Gentiles nor Jews, just the opposite, he's telling the Gentiles to STOP trying to be like the Jews in order to earn your way to Heaven by keeping the Law !! YOU DON'T HAVE T BE JEW........God doesn't see Jew or Gentile but just the FAITH of both Jews and Gentiles of both MALE & FEMALE !! I amazes me people can read that and think the Church has taken the place of the Jews BUT that there are still males and females, and they can't even understand that Juxtaposition has to be the same in both cases.
The JUXTAPOSITION is FAITH makes us whole, in all mankind, be we Jew, Gentile, Male, Female, Slave or Freeman !!