Charles Ellicott Commentary Romans 11:12

"Now if their fall, is the riches of the world, and their loss the riches of the Gentiles; how much more their fulness?" — Romans 11:12 (ASV)

And if the fall of the Jews had such good results, much more might be expected from their reinstatement.

Diminishing . . . fulness.—It is, perhaps, difficult to suggest a better translation.

The Apostle seems to have in view not only the supersession of the Jews by the Gentiles, but also, under the figure of a defeat in battle, the reduction of their numbers to a small remnant. And, on the other hand, he looks forward to their full and complete restoration, when every Jew shall be a member of the Messianic kingdom, and there shall not be one missing.

The full “complement,” as it were, of the nation is what is meant by “fulness;” its temporary reduction and degradation is expressed by “diminishing.”