In Genesis 30:4, Rachel uses her servant Bilhah in the same way, showing Leah's action with Zilpah was part of a competitive pattern between the sisters.

In Genesis 30:3, Rachel makes the identical offer to Jacob, showing Leah's act with Zilpah was the immediate precedent for her sister's request.

In Genesis 30:17, God again hears Leah, showing that her act of giving Zilpah was part of a continuing narrative of her seeking children and divine favor.

In Genesis 16:3, Sarah gives her servant Hagar to Abraham, a direct and earlier model for the same custom of surrogate motherhood through a handmaid.

Genesis 46:18 traces Zilpah's descendants entering Egypt — Gad and Asher, the sons born to Jacob through Zilpah after Leah gave her to him.

In Genesis 16:2, Sarah proposes this arrangement to Abram, providing the narrative origin of the 'giving a servant as wife' practice Leah later follows.