John Gill Commentary 1 Chronicles 4:1

"The sons of Judah: Perez, Hezron, and Carmi, and Hur, and Shobal." — 1 Chronicles 4:1 (ASV)

The sons of Judah: Pharez
The posterity of Judah in the line of Pharez, for he only is mentioned:

Hezron, and Carmi, and Hur, and Shobal .
Hezron was the son of Pharez, and Carmi is supposed to be Chelubai, or Caleb, the son of Hezron; and Hur the son of Caleb; and Shobal was the son of the second Caleb the son of Hur; see (1 Chronicles 2:5 1 Chronicles 2:9 1 Chronicles 2:19 1 Chronicles 2:50) .