Genesis 18:6, 9, 10

So Abraham hurried into the tent to Sarah. “Quick,” he said, “get three seahs of the finest flour and knead it and bake some bread.”

“Where is your wife Sarah?” they asked him. “There, in the tent,” he said.

Then one of them said, “I will surely return to you about this time next year, and Sarah your wife will have a son.” Now Sarah was listening at the entrance to the tent, which was behind him.