Komentarz do Diwrej ha-jamim I 22:2

to gather the strangers who had converted, because he did not wish to make Israelites perform rigorous labor. And so we find with Solomon below (II Chron. 2:1): “And Solomon counted, etc.”; (ibid. verse 17): “And he made of them seventy thousand who bear burdens.” And it is written further (ibid. 8:7): “And all the people remaining from the Hittites, etc., who were not of Israel, etc.”; (ibid. verse 9): “And of the Children of Israel, whom Solomon did not make slaves, etc.”