How can non-Muslim women (Christians, Jews, atheists, Zoroastrians, and others) be invited to Islam, and what are the best ways to do so? What is the ruling on a Zoroastrian woman marrying her brother, and what is the fate of her marriage and children after her conversion to Islam if she refuses to separate from her husband, assuming they both embrace Islam together?

The method of inviting non-Muslims to Islam varies depending on their types. The Magians permit incestuous marriages, such as marrying a sister, which is not allowed by any divine religions or laws. If one of them performed such an act and then embraced Islam, he will not be held accountable for what happened in the past. However, he must abandon this marriage after becoming Muslim, based on the Almighty's saying: ﴿And do not marry those [women] whom your fathers married, except what has already occurred. Indeed, it was an immorality and hateful [to Allah] and was a terrible way.﴾ And His saying: ﴿Prohibited to you [for marriage] are your mothers... and [prohibited is] that you combine in marriage two sisters, except what has already occurred. Indeed, Allah is Forgiving and Merciful.﴾ Islam abrogates what came before it, and the annulment of such a marriage after embracing Islam is a matter of consensus among scholars. The lineage of children from such a marriage is established, similar to marriages of شبهة (marriages based on misconception or doubt). As for the woman's refusal to separate after embracing Islam, that is her choice, but Islam has nullified this marriage. Her embracing Islam is better for her, even if she insists on remaining in this marriage, because there is no hope for the disbeliever in Allah's mercy.