Charles Ellicott Commentary 1 Chronicles 8:39

"And the sons of Eshek his brother: Ulam his first-born, Jeush the second, and Eliphelet the third." — 1 Chronicles 8:39 (ASV)

Eshek his brother —that is, the brother of Azel, and son of Eleasah (1 Chronicles 8:37). The elder line is first developed.