The Greek phrase “in other generations” is a way of referring to the past, with no limitations (compare Col 1.26 “the secret hidden from the ages and from the generations”). So Good News Translation In past times; in some languages “Before” or “Before this” or “Before now” will be sufficient.

Mankind was not told; “was not made known” (Revised Standard Version): again the use of the passive of the verb “to make known” (as in verse 3a). The implied actor in this passive voice and in the following passive “was revealed” is God. Some translators will want to say “God did not tell mankind the secret,” or “God did not tell people about this plan.” But the Greek verb may mean “to know,” so that it is possible to translate “… mankind did not know this secret.”

God has revealed it: here the verb “to uncover” is used (see the related noun in 1.17; 3.3). In the parallel Colossians 1.26b the verb “bring to light” is used; the meaning of both is the same, that is, both refer to God’s action of revealing a truth to mankind.

“The sons of men” (Revised Standard Version) is a Semitic phrase meaning “all mankind” (see its use in Mark 3.28).

To his holy apostles and prophets: see in 2.20 the apostles and prophets. His here is taken by most to refer to God (the implied actor in “was revealed”), but Westcott takes it to refer to Christ, which is also possible. It is to be noticed that here the adjective “holy” is used, and it must somehow distinguish the apostles and prophets as being in some way different from other Christians, all of whom are “the saints,” that is, dedicated to God, God’s people (see 1.1). As a group “the apostles and prophets” have a standing or a quality not shared by others. It should be noticed that the parallel passage in Colossians 1.21 has “to his saints,” all of God’s people, not just to one select group. Such a sharp contradiction between the two makes it very difficult to believe that the same person wrote both passages. The phrase “holy prophets” in Luke 1.70; Acts 3.21; 2 Peter 3.2 refers to the Old Testament prophets and is perfectly natural in a New Testament document. Nowhere else in the New Testament is the adjective hagios “holy” applied to the apostles (compare Rev 18.20). New English Bible translates “his dedicated apostles and prophets”; Barclay “God’s consecrated apostles and prophets” (similarly Phillips).

In rendering his holy apostles and prophets in the sense of “his dedicated apostles and prophets,” it may be necessary to indicate specifically how the apostles and prophets are dedicated or consecrated to God. One may sometimes use a statement such as “his apostles and prophets who have given themselves to serving God” or “the apostles and prophets whom God has especially appointed to serve him.” This means that the process of dedication or consecration can be viewed either from the standpoint of the activity of the apostles and prophets or in terms of what God did in appointing or commissioning them to serve him in these special functions.

The final phrase in verse 5 in Greek is “in spirit,” and it is taken by nearly all to refer to the Holy Spirit. The phrase means either (1) the Spirit did the revealing (“by the Spirit”; so Translator’s New Testament, New International Version, and others) or (2) God revealed by means of the Spirit (Good News Translation, Traduction œcuménique de la Bible, and others). If interpretation (1) is followed, then the translation must say “But now the Holy Spirit has revealed it to God’s holy apostles and prophets.”

There is a problem of double agency in the second part of verse 5. God is the primary agent who reveals, but it is by means of his Spirit. Therefore it may be necessary to translate the second clause of verse 5 as “God has now caused his Spirit to reveal this secret to his holy apostles and prophets.”

Quoted with permission from Bratcher, Robert C. and Nida, Eugene A. A Handbook on Paul’s Letter to the Ephesians. (UBS Handbook Series). New York: UBS, 1982. For this and other handbooks for translators see here .