Charles Ellicott Commentary 1 Chronicles 6:26

"As for Elkanah, the sons of Elkanah: Zophai his son, and Nahath his son," — 1 Chronicles 6:26 (ASV)

The Hebrew text reads: “Elkanah his son—Elkanah—Zophai his son,” etc. Zophai might mean the Zophite. The Septuagint has (1 Chronicles 6:25) “And sons of Elkanah, Amessi and Ahimoth;” (1 Chronicles 6:26) “Elkanah his son, Souphi his son,” etc. So the Syriac. That this is correct appears from comparison of Heman’s pedigree (1 Chronicles 6:35). The second Elkanah in 1 Chronicles 6:26 is therefore an intrusion, perhaps due to some scribe who remembered 1 Samuel 1:1, where Zophim occurs just before Elkanah. In 1 Chronicles 6:35, Elkanah is the son of Mahath, son of Amasai.

Perhaps Mahath is identical with the Ahimoth of 1 Chronicles 6:25; if so, the true reading of 1 Chronicles 6:25–26 would be: “And sons of Elkanah: Amasai his son, Ahimoth (Mahath) his son, Elkanah his son, Zophai his son,” etc. Zophai is to Zuph (1 Chronicles 6:35) as Chelubai (1 Chronicles 2:9) is to Chelub (1 Chronicles 4:11). Nahath looks like a transformation of Toah (1 Chronicles 6:34), and Eliab (1 Chronicles 6:27)—“El is father”—may be a by-form of Eliel (1 Chronicles 6:34) “El is el.” Jeroham and Elkanah go back to Eliel in 1 Chronicles 6:34, just as they spring from Eliab here. The two series again coincide.