Sigurd Grindheim, «What the OT Prophets Did Not Know: The Mystery of the Church in Eph 3,2-13», Vol. 84 (2003) 531-553
The purpose of this essay is two-fold. First, it argues that the inclusion of the Gentiles is referred to as a previously unrevealed mystery because it is based upon the abrogation of the Mosaic law and entails a degree of nearness to the Lord that exceeds the expectations of the old covenant. Second, it addresses the question of authorship. Assuming Pauline authorship as a working hypothesis, it shows that the use of the concept of mystery in Eph 3 is intimately linked with Paul’s terminology and thought world attested in the undisputed letters. It is unwarranted, therefore, to find proof of a post-Pauline development in the use of the term "mystery" in Ephesians.
replaced by "mystery". He observes that in the homologoumena verbs of speaking and hearing are typically used with gospel as the object (1 Cor 9,14; 15,1; 2 Cor 11,4.7; Gal 1,11.12; 2,2; 1 Thess 2,2), whereas in Ephesians this no longer is the case; it is "mystery" that is used instead (1,9; 3,3.5; 6,19)70.
Merklein has made too much of this evidence, however. In 1 Cor 2,6-7 Paul says that he speaks God’s wisdom in a mystery, an expression that refers to the gospel71. In Romans "gospel" is not used in this technical way at all but in 16,25-26 "mystery" is the object of gnwri/zw72. In 1 Cor 1,23 "Christ crucified" is used in this technical way and in 2 Cor 4,5 it is Jesus Christ as Lord (cf. 2 Cor 11,4; Col 2,6). Phil 1,15 refers to someone preaching Christ. In Gal 3,23 "faith" is probably used a circumlocution for "gospel" and in Phil 1,14 the technical term for the content of Paul’s preaching is lo/goj (cf. 1 Thess 1,6.8; 2,13; 2 Tim 4,2). Apparently, "the grace of God" can be used similarly (2 Cor 6,1; Col 1,6)73. This is ample evidence that, throughout the Pauline corpus, there is a number of terms Paul finds pertinent to denote the content of his preaching. We have also seen that there is a certain laxity in the use of the term in Ephesians. It has not become a term with a fixed meaning. It is therefore unwarranted to find evidence for a post-Pauline development in the employment of "mystery" as a technical term for the gospel in Ephesians.
The Jews and Gentiles being joined together in the same body represents the fulfillment of the prophecies regarding the re-creation of