Romans 11: Israel and Jesus, again

Would the Lord break his promises to Israel? Would the Lord forget Israel and create a new nation from the gentiles?
Although many Jews had rejected Jesus, the Lord can't break his promises to Israel; surely there were a remnant that believed in Jesus as the Messiah, that were saved by faith. Not only the remmant, but the Jews will be saved in greater numbers:

25 For I do not want you, brothers and sisters, to be uninformed of this mystery—so that you will not be wise in your own estimation—that a partial hardening has happened to Israel until the fullness of the Gentiles has come in; 26 and so all Israel will be saved;

Paul argues that the gentiles should not be arrogant, as if they Lord preferred them but not the Jews. He reminds that everything is under the Lord's control.