역대상 2:50의 주석

These were the sons of Caleb, the son of Hur, the firstborn of Ephrathah The interpretation is: These were the sons of Caleb. בֶּן חוּר is like בְּנוֹ חוּר, his son was Hur, and that Hur was the firstborn of Ephrath, his wife, not the firstborn of Caleb, and so it is explained above (verse 19): “And Caleb took to himself Ephrath, and she bore him Hur.” Another explanation [is that] “for these were the sons of, etc.” Hur was Caleb’s son, and he begot a son whom he named Caleb, and this is its explanation: And these were the sons of Caleb the son of Hur: Shobal, etc.

the firstborn of Ephrathah but not the firstborn of Caleb. This refers to Hur. So it appears to us.