I thought a short commentary on the "Nethinim" (Nathinim, Nethunim) would be fun. So here we go.
The word (given (ones) is used in verbal form in reference to the Levites until the post Exilic stories whereupon it takes on a new usage as a name of a specific non-Israelite people serving in the Temple. It is much complicated by the various descriptions from P,D,J but it is clear we have some conflict of opinions about the history and role of this group.
In Josh 9 we have an apparent late attempt to identify Nethinim with the Gibeonites. If you recall the story Yahweh instructs them to kill them but Joshua is conned into thinking they came from far away and he enters a treaty with them. He subsequently assigns them to be slaves as wood cutters and water fetchers for the whole assembly of Israel (It was apparently edited with additional references to the alter services "down to this day" that gives it away). Never again are they connected with the temple or alter.
According to the Jewish Encyclopedia: The picture of the Levites given in Leviticus, Numbers, the P portions of Joshua, and Chronicles is thought...to be a projection by the writers of the institutions of their own times into the distant past.
According to Ezra and Nehemiah upon return from exile suddenly we have a non-Israelite people called Nethinim who are apparently vital to Temple services. They now appear as a distinct family/clan living somewhere in an unknown city of Casiphia (shining white) led by a man name Iddo (timely). And their 'timely' assistance is given to the Temple to help purify the Israelites. Not everyone agreed with this practice of using foreigners in the Temple.
So, what we have so far suggests as Narkissos posted some years ago:
From a critical standpoint, there is little doubt that the name is really post-exilic, applying to a subordinate category of temple servants in the early 2nd temple arrangement (along with the "sons of the slaves of Solomon," Ezra 2:55; Nehemiah 11:3). Apparently they were slaves "given" to the temple as an offering by wealthy worshippers or rulers -- a Babylonian practice according to Lipinski, which seems to be directly condemned in Ezekiel 44:6-9: "Say to the rebellious house, to the house of Israel, Thus says the Lord GOD: O house of Israel, let there be an end to all your abominations in admitting foreigners, uncircumcised in heart and flesh, to be in my sanctuary, profaning my temple when you offer to me my food, the fat and the blood. You have broken my covenant with all your abominations. And you have not kept charge of my sacred offerings; but you have appointed foreigners to act for you in keeping my charge in my sanctuary. Thus says the Lord GOD: No foreigner, uncircumcised in heart and flesh, of all the foreigners who are among the people of Israel, shall enter my sanctuary."
It gets even more interesting from Rabbinic sources. Again, from the Jewish Encyclopedia:
This union of sacred service and social ostracism has led to the suggestion that the Nethinim were the descendants of the Ḳedeshot, or sacred prostitutes; and it may be pointed out that in the list in Ezra ii. there is a large number of feminine forms, as well as in the extra list contained in the Book of Esdras (v. 53-58). This latter list contains a reference to the "Bene Souba," with which may be compared the "Soba'im" of Ezek. xxiii. 42 (Hebr.). Both the Septuagint and Josephus refer to the Nethinim as "Hieroduli," which seems to imply that they were Ḳedeshot.
Sooo, the WT has decided to utilize this element of the Nethinim as foretelling the appointment of "Other Sheep" to important roles as assistants to the GB. Who were these Nethinim?
Well our choices seem to be: 1. con-men turned slaves, 2. foreign slaves sold to the Temple as offerings and condemned by Ezekiel or 3. Temple prostitutes recast as servants.