Al-Baqarah

And if he has divorced her [for the third time], then she is not lawful to him afterward until [after] she marries a husband other than him.¹ And if he [i.e., the latter husband] divorces her [or dies], there is no blame upon them [i.e., the woman and her former husband] for returning to each other if they think that they can keep [within] the limits of Allāh. These are the limits of Allāh, which He makes clear to a people who know [i.e.,understand].