Nowhere does it say "the church" is Israel now. And Paul says exactly what the promise is in Romans 9:9. The promise God made to Abraham

8 that is, the children of the flesh -- these [are] not children of God; but the children of the promise are reckoned for seed;

9 for the word of promise [is] this; `According to this time I will come, and there shall be to Sarah a son.'

10 And not only [so], but also Rebecca, having conceived by one -- Isaac our father --

11 (for they being not yet born, neither having done anything good or evil, that the purpose of God, according to choice, might remain; not of works, but of Him who is calling,) it was said to her --

12 `The greater shall serve the less;'

13 according as it hath been written, `Jacob I did love, and Esau I did hate.'