Genesis 29:26

29:26 “It is not our custom here,” Laban replied, “to give the younger daughter in marriage before the firstborn.

Genesis 19:31

19:31 Later the older daughter said to the younger, “Our father is old, and there is no man anywhere nearby to have sexual relations with us, according to the way of all the world.

Genesis 19:35

19:35 So they made their father drunk that night as well, and the younger one came and had sexual relations with him. But he was not aware that she had sexual relations with him and then got up.

Genesis 19:34

19:34 So in the morning the older daughter said to the younger, “Since I had sexual relations with my father last night, let’s make him drunk again tonight. Then you go and have sexual relations with him so we can preserve our family line through our father.”