βασίλειον ἱεράτευμα What is going on here?

1Pet. 2:9 ὑμεῖς δὲ γένος ἐκλεκτόν, βασίλειον ἱεράτευμα, ἔθνος ἅγιον, λαὸς εἰς περιποίησιν, ὅπως τὰς ἀρετὰς ἐξαγγείλητε τοῦ ἐκ σκότους ὑμᾶς καλέσαντος εἰς τὸ θαυμαστὸν αὐτοῦ φῶς·

LXX OG Exodus 19:6 ὑμεῖς δὲ ἔσεσθέ μοι βασίλειον ἱεράτευμα καὶ ἔθνος ἅγιον ταῦτα τὰ ῥήματα ἐρεῖς τοῖς υἱοῖς Ισραηλ

J.W. Wevers (Notes on Greek Text Exodus, 295) points out that this is a chaistic construction; adjective noun conjunction noun adjective; βασίλειον ἱεράτευμα καὶ ἔθνος ἅγιον. Wevers notes this is not a common pattern in Exodus LXX OG.

J.N.D. Kelly (1Peter BNTC 1969) calls this into question. He points out that βασίλειον as an adjective is extremely rare in biblical Greek. He prefers to read βασίλειον as an independent neuter collective noun referring to “a royal household” followed by another collective noun ἱεράτευμα in series of several collectives βασίλειον ἱεράτευμα, ἔθνος ἅγιον, λαὸς εἰς περιποίησιν. In support for reading βασίλειον as a collective noun Kelly points out the Hebrew (MT) behind the Exodus 19:6 LXX OG is comprised of two nouns. However he chooses to ignore that MT does not show two independent nouns. It has a noun in construct state followed by a noun in the “genitive”. Aquila renders this βασιλεία ἱερέων. We probably don’t know how the various readings represent by Aquila, LXX, Theodotian and Symmachus, Jubilees came into existence but it isn’t really valid to use the MT reading mamleket kohanim as support for understanding βασίλειον ἱεράτευμα as two independent nouns.

The most recent translation of the Exodus 19:6 LXX by Larry J. Perkins in NETS reads βασίλειον ἱεράτευμα as an adjective followed by a collective noun.

And you shall be for me a royal priesthood and a holy nation. These words you shall say to the sons of
Israel.

I do not know what reading is behind this translation but it appears that J.W. Wevers , the editor of the Göttingen Septuagint Exodus, accepted the reading βασίλειον ἱεράτευμα. I could ask Albert Pietersma, the general editor of NETS, and update this post later. Here is a general comment from Larry J. Perkins introduction to Exodus NETS:

The NETS translation of the book of Exodus has followed the edition of the Greek text prepared by John William Wevers (Septuaginta: Vetus Testamentum Graecum Auctoritate Academiae Scientiarum Gottingensis ed- itum II.1: Exodus [Göttingen: Vandenhoeck & Ruprecht, 1991]).
This English translation has not altered Wevers’ edited Greek text of Exodus, except infrequently in re- lation to punctuation..

Once again, here are the different forms of the text:

βασιλεία ἱερέων - Aquila

βασιλείαν ἱερεῖς - Theodotian and Symmachus, Rev. 1:6

βασιλείαν καὶ ἱερεῖς - Rev. 5:10, Jubilees 16:18 (R.H. Charles Rev. ICC v1 p118)

βασίλειον ἱεράτευμα - LXX OG 1Peter 2:9

Cataloging the readings from the Greek versions does not in and of itself settle the question about how the text is being used in 1Peter 2:9 and Rev. 1:6, 5:10. The form of this text in Revelation 1:6, 5:10 lends some support to the Kellly's suggestion that we have here two independent nouns. Aquila's version βασιλεία ἱερέων is only one which could not be read as two independent nouns. This form of the text is not found in the New Testament.