Genesis 16:1-3

1Now Sarai, Abram’s wife, had not been able to bear children for him. But she had an Egyptian servant named Hagar.

2So Sarai said to Abram, “The Lord has prevented me from having children. Go and sleep with my servant. Perhaps I can have children through her.” And Abram agreed with Sarai’s proposal.

3So Sarai, Abram’s wife, took Hagar the Egyptian servant and gave her to Abram as a wife. (This happened ten years after Abram had settled in the land of Canaan.)