Bede

Therefore Sarai, Abram's wife, had borne no children, but she had an Egyptian maidservant named Hagar. She said to her husband, "Behold, the Lord has prevented me from bearing children, so go into my maidservant; perhaps I shall obtain children by her." And when he agreed to her request, she took Hagar the Egyptian maidservant after ten years of dwelling in the land of Canaan, and gave her to her husband as a wife. He went in to her, and when she saw that she had conceived, she despised her mistress, etc. …

Commentary on Genesis (Hexaemeron) ↗