John Gill Commentary 1 Chronicles 7

Now the sons of Issachar were Tola, Puah, Jashub, and Shimron,
four .
] The same number is given, (Genesis 46:13) with a small variation of two of their names, there called Phuvah and Job, from which so many families sprang, mentioned (Numbers 26:23Numbers 26:24) , where the names are the same as here.

And the sons of Tola
The eldest son of Issachar, whose posterity are only reckoned by name:

Uzzi, and Rephaiah, and Jeriel, and Jahmai, and Jibsam, and Shemuel,
heads of their father's house, to wit, of Tola ;
the principal man of his family:

[they] were valiant men of might in their generations ,
famous for their courage and military exploits, though they sprang from Tola, whose name signifies "a worm"; and which name Bochart ^F11 conjectures was given him by his parents, because he was so weakly that they had no hopes of raising him; and yet from him sprung such mighty men, and from them such a numerous race, as follows:

whose number was, in the days of David, two and twenty thousand and six
hundred ;
besides those of the posterity of Uzzi, after mentioned. This was at the time Joab took the number of Israel, by the order of David, (1 Chronicles 21:5) .

FOOTNOTES:

• F11: Hierozoic. par. 2. l. 4. c. 21. col. 630.

And the sons of Uzzi; Izrahiah
Including his posterity:

and the sons of Izrahiah; Michael, and Obadiah, and Joel, Ishiah, five ;
together with their father, all reckoned the sons of Uzzi:

all of them chief men ;
in their father's house, heads of families.

And with them, by their generations, after the house of their
fathers, were bands of soldiers for war
Companies of men of military courage and skill, who could and did go out to war upon occasion:
six and thirty thousand [men] ;
besides the 22,600 Tolaites, (1 Chronicles 7:2) , for they had many wives and sons ;
having many wives, they had many sons; polygamy was the cause of their large numbers; and that they gave into for the sake of the multiplication of Abraham's seed, according to the divine promise.

And their brethren among all the families of Issachar
As those of Puah, Jashub, and Shimron, (1 Chronicles 7:1)

were men of might ;
valiant and courageous:

reckoned in all, by their genealogies, fourscore and seven thousand ;
that is, including with these those of Tola and Uzzi before given.