Genesis 16:2-4

Sarai said to Abram, “Look, the LORD has not allowed me to have children, so have sexual relations with my slave girl. If she has a child, maybe I can have my own family through her.” Abram did what Sarai said. It was after he had lived ten years in Canaan that Sarai gave Hagar to her husband Abram. (Hagar was her slave girl from Egypt.) Abram had sexual relations with Hagar, and she became pregnant. When Hagar learned she was pregnant, she began to treat her mistress Sarai badly.