So, has god rejected his people then? By no means! Remember when Elijah bitched that the Israelites had killed all the other prophets and were gunning for him, too? And god said he saved 7000 men from Baal worship? Well, now he's decided to save some number of the population, selected at random rather than through their good works. The rest he has hardened against Jesus, while at the same time punishing them for all eternity. Totally fair and just, that god. And why did he do this? Well, to teach the gentiles about grace, because they're proving easier to convert to this new religion than those argumentative, riot-prone Jews.
Paul informs us that he's saying this to the Gentiles in order to make the Jews jealous and to convince them to come over to his side. He also tells them they're just branches that have been grafted onto a tree, not the root, so be careful, because look what god did to the old branches.
But not to fear! This is all temporary, and one day the Jews will accept Jesus and Israel will be whole again. Until then, though, they're our enemies.
Paul urges us to turn our minds and bodies over to god. Then he says some things that would be good advice if they were taken out of context, but given that they are written in the bible, they're worth the proverbial hill of beans. See chapter 11, for example.
Nonetheless: Judge yourself fairly, and remember that any organisation needs more indians than chiefs. Only use your talents in proportion to your faith. Love should be sincere, hate is evil. Keep hold of the good things. Be nice to other people. Work hard, be hopeful, but be patient in troubled times, keep praying. Be hospitable to strangers. Don't swear, rather, bless people. Be empathetic to others' feelings. Live harmoniously, striving to get to know people from other social classes. Don't be arrogant. Don't seek revenge,that's god's job, rather act honourably. If your enemy is suffering, give him food and drink. Don't be subsumed by evil, but by good.