Sad · 38:34

34. And I tested Solomon and put on his chair part of a child, and that was when he swore by Allah that he will sleep with all of his wives and each one of them will bring forth a horseman to strive in Allah’s way. But he did not say in this oath of his: “if Allah wills”. So he slept with all of them, but none of them gave birth except one who gave birth to part of a child. Then Solomon repented to his Lord.