Genesis 16:2

And 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 by her. And Abram listened to the voice of Sarai .

so she said to Abram, “The Lord has kept me from having children. Go, sleep with my slave; perhaps I can build a family through her.” Abram agreed to what Sarai said.

And Sarai said unto Abram, Behold now, the Lord hath restrained me from bearing : I pray thee, go in unto my maid; it may be that I may obtain children by her. And Abram hearkened to the voice of Sarai.