Is it permissible to curse those who commit sin?
Question

                Among us, if one man curses another and the curse receives no response because he does not deserve that, does it come back on the first man or not? Is it permissible to curse a woman on the grounds that she is not wearing hijab?.
Praise be to Allah.
    Cursing is not one of the attributes of the believer who has 
    attained perfect faith. It was narrated by Imam Ahmad in his Musnad 
    and Imam al-Tirmidhi in his Jaami’ from ‘Alqamah that ‘Abd-Allaah ibn 
    Mas’ood (may Allaah be pleased with him) said: The Messenger of Allaah  
    (peace and blessings of Allaah be upon him) said: “The believer is not a 
    slanderer, one who curses a great deal, one who indulges in obscenity or who 
    in engages in foul talk.” Al-Tirmidhi said: It is a hasan ghareeb hadeeth. 
    And it was narrated in al-Saheehayn from Thaabit ibn al-Dahhaak that 
    the Prophet  (peace and blessings of Allaah be upon him) said: “Cursing 
    a believer is like killing him.” 

    Based on this, it is not permissible for a believer to curse 
    anyone among his Muslim brothers except those whom Allaah cursed in His Book 
    or whom the Messenger  (peace and blessings of Allaah be upon him) 
    cursed. It is not permissible to curse one who commits a sin because of his 
    or her sin, such as a woman who is not wearing hijab and the like. Rather 
    the Muslim should advise her and encourage her to wear hijab using kind and 
    gentle methods. If anyone curses someone who does not deserve to be cursed, 
    there is a stern warning that the curse will come back on the one who utters 
    it if it is not justified. This is indicated by the report narrated by 
    Abu’l-Darda’ (may Allaah be pleased with him) who said: The Messenger of 
    Allaah  (peace and blessings of Allaah be upon him) said: “When a person 
    curses something, the curse ascends to heaven, and the gates of heaven are 
    closed to it. Then it comes back down to earth and the gates of earth are 
    closed to it. Then it looks right and left, and if it does not find anywhere 
    to go, it goes to the one who was cursed, and if he deserves it (it befalls 
    him), otherwise it goes back to the one who uttered it.” Narrated by Abu 
    Dawood in his Sunan.  

    And Allaah is the Source of strength. May Allaah send 
    blessings and peace upon our Prophet Muhammad and his family and companions. 
    End quote.