וַתֹּ֣אמֶר לֵאָ֗ה נָתַ֤ן אֱלֹהִים֙ שְׂכָרִ֔י אֲשֶׁר־נָתַ֥תִּי שִׁפְחָתִ֖י לְאִישִׁ֑י וַתִּקְרָ֥א שְׁמ֖וֹ יִשָּׂשכָֽר׃
Lalu kata Lea, “Allah telah memberikan upahku, karena aku telah memberikan hamba perempuanku kepada suamiku.” Maka ia menamainya Isakhar.
Ramban
WHEN LEAH SAW THAT SHE HAD LEFT OFF BEARING SHE TOOK ZILPAH HER HANDMAID, etc. I do not know what motivated this deed of Leah and why she gave her handmaid to her husband for she was not barren that she should hope to have children through Zilpah, and it is not natural for women to increase the number of their husbands’ wives. We must, however, say that the matriarchs were prophetesses,108Bereshith Rabbah, end of Chapter 72. who knew that Jacob was destined to establish twelve tribes, and Leah desired that the majority of his sons be from her or from her handmaid, who was in her power, so that her sister Rachel would not prevail over her with respect to the number of her sons. Therefore, she said, G-d hath given me my share, because I have given my handmaid to my husband.109Verse 18 here. Jacob also came unto her on account of this, i.e., that he raise many sons for he knew it to be so, as our Rabbis have said.110Bereshith Rabbah 70:17. Jacob was also aware that he was destined to establish twelve tribes.
It is possible that knowing that the Land had been given to their children, and realizing that Abraham and Isaac had not had many children, Jacob wanted to have many wives in order to increase his progeny so as to inherit the Land, for a fourth generation shall come hither again,111Above, 15:16. and so Leah wanted to give him her handmaid so that he would not wed a stranger.
It is possible that knowing that the Land had been given to their children, and realizing that Abraham and Isaac had not had many children, Jacob wanted to have many wives in order to increase his progeny so as to inherit the Land, for a fourth generation shall come hither again,111Above, 15:16. and so Leah wanted to give him her handmaid so that he would not wed a stranger.