Luke 20:28-32

‘And they asked him, saying, “Teacher, Moses wrote to us, that if a man's brother die, having a wife, and he be childless, his brother should take the wife, and raise up seed to his brother. There were therefore seven brothers, and the first took a wife, and died childless; and the second, and the third took her, and likewise the seven also left no children, and died. Afterward the woman also died.”

His questioners cited a case where the levirate principle had been applied to seven brothers one by one, with each marrying the woman who had been left a widow by the previous brother when the previous brother died. She had thus married all seven brothers.