Many are called and few are chosen...
God grafts in those whom he has chosen. Paul calls those who follow Christ the Israel of God.
Paul also lets us know that we are now a part of Israel.
16 And as many as walk according to this rule, peace be on them, and mercy, and upon the Israel of God.
12 That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
14 For he is our peace, who hath made both one, and hath broken down the middle wall of partition between us;
Paul also lets us know that due to election not all of Israel is Israel...
6 Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel
For those who have not come to this knowledge before, there is National Israel and Saved or Spiritual Israel.