God told Abraham that his people would be chosen. Do you think God breaks his promises?
The promised blessings are conditioned upon obedience and turn into terrible curses upon disobedience:
However, if you do not obey the LORD your God and do not carefully follow all his commands and decrees I am giving you today, all these curses will come upon you and overtake you... (Deuteronomy 28:15)
And so they were chosen to receive Christ and to include all in His promise to mankind.