And Laban gave unto his daughter Leah Zilpah his maid, [for] an handmaid. It was usual to have many given them at this time, as Rebekah seems to have had, Genesis 24:59; but Leah had but one, and this was all the portion Jacob had with her. The Targum of Jonathan is,
"and Laban gave her Zilpah his daughter, whom his concubine bore unto him:''
hence the Jews say q, that the daughters of a man by his concubines are called maids.
q Pirke Eliezer, c. 36.