In keeping with the demands of English discourse structure, a pronominal reference in Greek (literally “those ones”) is made explicit by the Good News Translation: the Jews (see Jerusalem Bible and New American Bible).
The phrase abandon their unbelief (literally, “no longer remains in unbelief”) may be rendered as “no longer refuse to believe” or “give up not believing.” On the other hand, this may also be expressed positively as “return and believe” or “change and believe.”
Will be put back in the place where they were is literally “will be grafted in.” See the comments on grafting at verse 17.
Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on Paul’s Letter to the Romans. (UBS Handbook Series). New York: UBS, 1973. For this and other handbooks for translators see here .