She raised a knife against him and threatened him so he would divorce her. Does the divorce count as such?
Question

                During an argument with my wife, she raised a knife against me and threatened me so that I would divorce her and I said to her: You are divorced, so as to put a stop to the matter, but I did not really intend to divorce her. Does this divorce count as such?.
Praise be to Allah.If you were afraid that 
    your wife would carry out her threat to attack you with the knife that she 
    had with her, then this comes under the heading of being forced, and the 
    divorce does not count as such. Ibn al-Qayyim (may Allaah have mercy on him) 
    said: The Sahaabah issued fatwas saying that a divorce issued under 
    compulsion does not count as such. It is narrated in a saheeh report from 
    ‘Umar that a man suspended himself from a mountain by a rope to collect 
    honey and his wife came and said: Either I cut the rope or your divorce me. 
    He adjured her by Allaah and she insisted so he divorced her. He came to 
    ‘Umar and told him about that, and he said to him: Go back to your wife, for 
    this is not a divorce. The ruling that it does not count as a divorce was 
    also narrated from ‘Ali, Ibn ‘Umar and Ibn al-Zubayr (may Allaah be pleased 
    with them). End quote from Zaad al-Ma’aad (5/208). 
And he (may Allaah have 
    mercy on him) said: Imam Ahmad said in the report of Abu’l-Haarith: If a man 
    who is forced issues a divorce, the divorce is not binding; if what was done 
    to Thaabit ibn al-Ahnaf is done to him, then he is forced, because they 
    squeezed Thaabit’s foot until he divorced his wife, then he went to Ibn 
    ‘Umar and Ibn al-Zubayr, and they did not think it counted as anything, as 
    Allaah says (interpretation of the meaning): “except him who is forced 
    thereto and whose heart is at rest with Faith” [al-Nahl 16:106]. Imam 
    al-Shaafa’i (may Allaah have mercy on him) quoted this verse as evidence 
    that the divorce issued by one who is forced does not count as such. 
In Sunan Ibn Majaah 
    it is narrated from Ibn ‘Abbaas (may Allaah be pleased with him) that the 
    Prophet  (peace and blessings of Allaah be upon him) said: “Allaah has 
    pardoned my ummah for mistakes, what they forget and what they are forced to 
    do.” End quote from I’laam al-Muwaqqi’een (4/51). 
In al-Ikhtiyaaraat 
    by Shaykh al-Islam it says: The divorce issued by one who is forced does not 
    count. Force or compulsion happens by means of an explicit threat or when he 
    thinks it most likely that he or his property will be harmed even if there 
    is no explicit threat. He said elsewhere: The idea that the threat should be 
    thought mot likely to be carried out is not correct, rather the correct view 
    is that the likelihood of the threat being carried out or not should be 
    equal; then it is a case of compulsion. End quote from al-Fataawa 
    al-Kubra (5/568). 
But if you knew that your 
    wife would never harm you, or you could put a stop to her threat without 
    causing harm, then you were not forced in that case, and your divorce counts 
    as such. 
What we have mentioned here 
    is the ruling and guidelines on this issue. As for the ruling in your case, 
    the details must be examined further, hence we say that you have to refer to 
    the shar’i court or to a trustworthy scholar in your own land, so that he 
    can hear from both of you and determine whether this was a case of force or 
    not. 
And Allaah knows best.