Jurisprudential description of Al Khul`
Scholars differed about Khul` whether it is an annulment or irrevocable divorce according to two views:
The first view is:
It is an annulment which is one of the two views of Al Shafi`y, Imam Ahmad, the view of Shaykh-ul-Islam Ibn Taymiyah, (1) and the view of Ibn `Abbas. Ibn `Abbas (peace be upon him) held the following Ayah as a proof: "The divorce is twice" then he said: "Then there is no sin on either of them if she gives back (the Mahr or a part of it) for her Al Khul` (divorce)."
Then he said: "And if he has divorced her (the third time), then she is not lawful to him thereafter until she has married another husband."
Allah has mentioned two-times divorce, then Khul` then one-time divorce. So, if Khul` is a type of divorce, they will be four divorces. Furthermore, it is a separation without using the words of divorce and intention, so it is an annulment.
The second view is:
It is an irrevocable divorce which is the view of Imam Malik, Al Awza`y, and the people of opinions. The proof is that a wife pays a compensation for separation which is owned by the husband [i.e., divorce], so he does not possess to annul the marriage, so it is a type of divorce. Moreover, a husband mentions the implicit words of divorce with the intention of separating from her; so it is a type of divorce.
The correct view is the first, and Allah knows best.
The benefit of this disagreement is:
If we say that Khul` is a type of divorce, so it will be counted one-time divorce and the husband shall have two more divorces. When a husband accepts Khul` three times, she will be divorced thrice and shall not be lawful for him until she marries another man and the second man divorces her willingly or dies. However, if we consider it an annulment, the wife shall not be prohibited to her husband even if he accepts Khul` one hundred times; this case is done when a husband uses words other than the words of divorce and he did not have the intention to divorce her.
Nevertheless, if the wife pays a ransom to separate from her husband using one of the words of divorce, it will be considered a divorce without any disagreement. If Khul` is done by the implicit words of divorce or the words of Khul` or ransom and the husband has the intention of divorce, it will be considered a divorce because he has the intention to apply divorce. And Allah knows best!
(1) Majmu` Al Fatawa 19/284.