NET
10 One of them said, “I will surely return to you when the season comes round again, and your wife Sarah will have a son!” (Now Sarah was listening at the entrance to the tent, not far behind him.
Darby
10 And he said, I will certainly return to thee at [this] time of the year, and behold, Sarah thy wife shall have a son. And Sarah was listening at the tent-door, which was behind him.
KJV
10 And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard [it] in the tent door, which [was] behind him.