1 Chronicles 3:6 - Matthew Poole's English Annotations on the Holy Bible

And he had two other sons called by the same names, 1 Chronicles 3:8, but they were by differing wives; and probably they were then distinguished by some additional clause or title, which is here omitted, because it was now needless for us to know it; or the two first were dead before the two second were born, and therefore the names of the deceased were given to these to preserve their memory.