Genesis 16:3-4

So 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.) So Abram had sexual relations with Hagar, and she became pregnant. But when Hagar knew she was pregnant, she began to treat her mistress, Sarai, with contempt.