If an Apostate Repents What is the Ruling on His Wife? And Are His Children Legitimate?

Question :

If an apostate repents and returns to Islam with a sincere intention for Allah, is it right for him to return his wife to his house now that he is complying with all of the pillars of Islam with sincerity, faith, belief and Tawhid? And what atonement can he make after he has repented? And are his children born before his repentance legitimate?

Answer:

If the cause of the apostasy was before the consummation of the marriage, and the seclusion which necessitates the waiting period, then the marriage is annulled and in that case, his wife is not permissible to him, except with a new contract. If that occurred after the consummation or the seclusion which necessitates the waiting period, then the matter rests upon the expiry of the waiting period. If he repents before the expiry of the waiting period, she is his wife, but if it happens after the expiry of the waiting period or later, then the scholars hold that she is not permissible to him, except after a new contract. And some of the scholars hold that she is permissible to him, if he returns to her, for the expiry of the waiting period removes his authority over her and it does not make her forbidden to him, if he returns to Islam. And based upon these two situations, the ruling on this man becomes clear regarding his returning to his wife.

As for what has passed, sincere repentance cuts off what went before it, according to the Words of Allah, Most High:
"Say to those who have disbelieved, if they cease (from disbelief). their past will be forgiven. But if they return (thereto), then the examples of those (punished) before them have already preceded (as a warning)."

The Prophet said to 'Amr bin Al-'As, may Allah be pleased with him:
"Verily, Islam demolishes what went before it."

Regarding the children, if he considers that the marriage remains valid, due to his following those who do not consider one abandoning prayer a disbeliever, or he did not know that one who abandons prayer is a disbeliever, then his children are his and they belong to him. However, if he knew that abandoning prayer is disbelief and that his wife was not permissible to him when he abandoned prayer, and that having sexual intercourse with her was forbidden, then his children do not belong to him in that case.

And having said that, this matter is one of those great and serious matters that some people have been tested with today.

Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 5 Pages 426-427