וַיִּתֵּ֤ן לָבָן֙ לָ֔הּ אֶת־זִלְפָּ֖ה שִׁפְחָת֑וֹ לְלֵאָ֥ה בִתּ֖וֹ שִׁפְחָֽה׃
라반이 또 그 여종 실바를 그 딸 레아에게 시녀로 주었더라
Rashi
ותלד זלפה AND ZILPAH BARE — In the case of all Jacob’s wives there is mention of their having been with child (i. e. Scripture states ותהר) except in the case of Zilpah. This was because she was the youngest of all and quite a child in age so that her being with child was not noticeable (Genesis Rabbah 71:9) Laban had given her to Leah in order to deceive Jacob — that he might not perceive that they were bringing Leah to him in marriage — for thus was the custom: to give the elder handmaid to the elder daughter, and the younger handmaid to the younger daughter.
Or HaChaim
לה לשפחה. as a maidservant for her. The Torah was careful to add the word לה, as I have already explained in connection with verse 24.