The genealogy of the Levites (ch. 6) is at the center of the genealogical section of 1 Chronicles (chs. 1–9). It’s a long and complexly organized passage.
In general, it divides into two sections: The genealogies of the priests and Levites (vv. 1–53) and the cities assigned to priests and Levites (vv. 54–81). The first section is organized chiastically (see the slightly different analysis in Mark Boda’s 1 Chronicles, 73):
A. Genealogy of the priests, vv. 1–15
B. Genealogy of Levitical clans, vv. 16–30
C. Levitical singers, vv. 31–47
B’. Levites given to serve tabernacle, v. 48
A’. Duties of the priests, vv. 49–53
Verse 48 is something of an outlier. It’s plausible to suggest that it links back to vv. 31–32, forming a frame around the genealogies of Levitical singers. Verses 31–32 and 48 share a number of terms: service, tabernacle, house. Yet it seems best to me to link verse 48 with the generic genealogy of vv. 16–30. The Levites listed in vv. 16–30 perform the duties of Levites, what verse 48 calls (oddly) the “service of the tabernacle of the house of God.” The singers perform a different ministry in a different place; they are appointed for the service of song before the ark (v. 31), at the tent of David rather than the tabernacle of Moses.
That skeletal outline smooths over some of the complexities of the text’s texture. First, the chapter begins with a list of the three sons of Levi, in the order Gershon, Kohath, and Merari (v. 1). After recording the descendants of Aaron (who is from Kohath through Amram, vv. 2–3), verse 16 repeats verse 1: “The sons of Levi: Gershom, Kohath, and Merari” (the alternate spelling “Gershon/Gershom” is in the Massoretic Text). So the genealogy of the priests is framed by the list of Levi’s sons, or verse 16 marks a resumption of the genealogy begun in verse 1.
Second, the most extended genealogy of the three sons of Levi (vv. 16–30) unfolds in three cycles of three:
1. List of three sons: Gershom, Kohath, Merari, v. 16
2. Sons of Gershom, Kohath, Merari, vv. 17–19
3. Descendants of Gershom (7 generations), Kohath (10 gens), Merari (7 gens), vv. 20–30
That triple pattern returns at the end of the chapter. After listing the cities given to the Aaronic priests from the tribal areas of Judah and Benjamin (vv. 54–60), the Chronicler lists the cities of the other Levitical clans in two cycles of three:
1. Number of cities given to Kohath (10), Gershom (13), Merari (12), vv. 61–65
2. List of cities given to Kohath, Gershom, and Merari, vv. 66–81
Note that the order of the sons has changed: Kohath has taken first position in the inheritance. That revised order is first introduced at the center of the genealogy, with the list of Levitical singers and musicians. Heman the Kohathite is listed first (vv. 33–38), with Asaph of Gershom at his right hand (vv. 39–43) and Ethan of Merari on his left (vv. 44–47).
Intriguingly, that change in the order of the clans is accompanied by a reversal in the direction of the genealogy itself. Instead of tracing the descendants from Levi to Heman, Asaph, and Ethan, the Chronicler moves from the three chief singers back to Israel (in the case of Heman) or Levi (for the other tw0). When the Chronicler gets to the Levitical singers, at the very center of his genealogy, time backs up (cf. the backward genealogy of Jesus in Luke 3). One senses something profound is going on. One is at a loss to explain it.