Mystery. — The word always means throughout St. Paul’s writings something which, though not to be known or fully comprehended by unassisted human reason, has been made known by direct divine revelation. It is therefore not to be taken in this passage in its usual sense, of something hidden and concealed from all except a few, but rather of all such truths as though previously hidden, had been made manifest by the gospel.
It is thus applied to the whole or any part of the Christian system. To the whole, as in Romans 16:25; 1 Corinthians 2:7-10; Ephesians 1:9; Ephesians 6:19; Colossians 1:26-27; Colossians 2:2; 1 Timothy 3:9; 1 Timothy 3:16. To any part, as (a) the admission of the Gentiles, Ephesians 3:3 et seq., and partly here; (b) the mystical union of Christ and His Church which is typified in marriage, Ephesians 5:32; (c) the transformation of the “quick” at the resurrection, 1 Corinthians 15:51; and (d) the opposition of Antichrist to the gospel, 2 Thessalonians 2:7.
Here the reference is to the whole of the divine purpose as shown in the dealings with Jew and Gentile, and especially in the present exclusion and future re-admission of the former. This last point the Apostle goes on to prove.
Blindness. — Rather, as in the margin, hardness, a hardening of the heart so that the gospel could not find entrance into it.
In part. — These words qualify “Israel.” The hardness extends over some, but not over all. There were Jewish as well as Gentile converts in Rome itself.
The fulness of the Gentiles. — As above, the complete number; the full complement of the Gentiles.