Genesis 16:2-3

2And Sarai said to Abram, “Behold now, the Lord has prevented me from bearing children. Go in to my servant; it may be that I shall obtain children
Hebrew be built up, which sounds like the Hebrew for  children
by her.” And Abram listened to the voice of Sarai.
3So, after Abram bhad lived ten years in the land of Canaan, Sarai, Abram’s wife, took Hagar the Egyptian, her servant, and gave her to Abram her husband as a wife.

Genesis 30:9

9When Leah saw that she had ceased bearing children, she took her servant Zilpah and cgave her to Jacob as a wife.
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