Because that she had been married to seven husbands, whom Asmodeus the evil spirit had killed, before they had lain with her. Do you not know, said they, that you have strangled your husbands? you have had already seven husbands, neither was you named after any of them.
Read Chapter 3
Bede
AD 735
Sarah, Raguel’s daughter, in a city of the Medes, who had been given to seven husbands whom a demon killed as soon as they went in to her, figuratively denotes the mass of the Gentiles. Their teachers all knew about life in this world only, which runs a course of seven days, but were unable to say anything about eternal life. And so they were all carried off by the devil inasmuch as they were given over to idolatry until the true bridegroom, our Lord, came. He overcame the enemy and through faith united them (i.e., the Gentiles) to himself, as Tobias took Sarah to wife after tying up the devil on the instructions and with the aid of the archangel. - "On Tobit 3.7–8"
