Romans 11:5,6

As there was a remnant then, so also is there a remnant now. That there should be so is due not to any human merit on the part of those exempted from the fate of their nation, but to the spontaneous act of the divine grace selecting them from the rest. These two things,” grace” and “works,” really exclude each other.

The Apostle reverts somewhat parenthetically, and because his mind is full of the thought, to his idea of Romans 9:11. We have here also a break in the train of argument. After establishing the fact that there is this remnant, the Apostle inquires how there came to be one. The reason was because the mass of the people trusted to their own works instead of relying upon grace; therefore grace deserted them, and they were left to a judicial blindness.