Keil & Delitzsch, on 1Chr 4:14

“Maonathi beget Ophra, and Saraia begot Joab the father of the Valley of artificers: for artificers were there.”

“And Meonothai,.... Another son of Othniel: begat Ophrah; and Seraiah, the brother of Othniel, begat Joab; not David's general, but another of the same name, who lived long before him, see Ch1 2:54. the father of the valley of Charashim: of the inhabitants of the valley, or the prince of them, called the valley of craftsmen, Neh 11:35 the reason of which is here given: for they were craftsmen; that dwelt in it, carpenters and smiths, both which the word signifies, men that wrought in stone, wood, and iron.”

Imported from an open dataset — not yet checked against the printed edition.