John Gill Commentary 1 Kings 5:14

"And he sent them to Lebanon, ten thousand a month by courses; a month they were in Lebanon, and two months at home; and Adoniram was over the men subject to taskwork." — 1 Kings 5:14 (ASV)

And he sent them to Lebanon, ten thousand a month by courses ,
&c.] In their turns; these are the servants of his he proposed to be with Hiram's servants, assisting in cutting down the trees, and squaring the timber in Lebanon, (1 Kings 5:6) ;

a month they were in Lebanon, [and] two months at home ;
that they might not be overworked; for they wrought but four months in the year in the hard service in Lebanon, the rest of their time was spent in managing their domestic affairs; these were Israelites:

and Adoniram [was] over the levy :
the same that was over the tribute or the collectors of the tax, (1 Kings 4:6) ; and, according to the Targum, these were such persons.